First, the second part of that title isn't true. You simply forgot who loves you, or you need to find more that do. But there may be times where you feel alone and depressed. Almost everyone has that occasionally or is strong enough to admit it. It's not easy to talk about, but loneliness, feeling unwanted, and even self-hate from time to time are extremely common. If isolation drags on for weeks, you'll want help from healthcare experts, but if it's not so severe and happens on occasion I will suggest a few things.
Compile the love you've felt. Whether it be a handwritten letter from your mom, a photo of you hanging out with friends on your birthday, and any awards you've won. They don't have to be recent, recognition spans your whole life. And they don't have to be physical either. Take screenshots of kind words from others, like Facebook comments. When I feel like I'm not being cared about, I go down my social media timelines and read comments that reassure me that I am loved. Doing that gives the perspective that others have cared about me before, and they will again. By realizing this, I care about myself. It's a process and never will happen immediately. One can't instantly "snap out of it". It "takes time" as the trite but true saying goes.
Give up on something worth dropping. Burdens are bedfellows with loneliness. Some people who'd like to have more social life are crushed by the rat race or their own compounded fears which hold them back. By cutting off the fat, it frees you to take on more meaningful things. Less worry means more freedom to self explore and pursue interests. When you find yourself especially stressed or anxious, those are otherwise-unpleasant moments you can use to your advantage. Especially if you’re crying and in a lot of anguish, determine in a flash what’s worth keeping, and visualize it like this: you are a burning building. If you could rush into yourself and save only a handful of things to take to a new you, what will they be? Take a mental inventory, or even better, write them down so you can visualize it, and put it aside until you feel more rational. Then look at it again, and join your thoughts of the now with what you had felt then.
Celebrate your similarities AND differences. Too many people make the mistake of singling out what’s common or how they’re different. This is defective, too-filtered thinking because success is neither completely familiar or alien: it’s both. All of us are humans and subject to emotions. By consequence, all of us have problems but some of us deal with them more effectively than others. We are all variations on a common theme. If you’re concerned about body image, it’s good for all humans to be healthy. But it’s unachievable to duplicate someone else’s figure. You need to do what’s right for you and being inspired by someone isn’t the same as cloning them: it’s taking your hero’s “recipe” and improvising a new mix with it.
Be brave about what you really like. Many people have secret “guilty pleasures”, be they pop songs or other recreational activities. If it does no harm to your health and well-being, why must it be guilty? Strip away the “layers of mindfat” and be earnest. This prepares you to meet other likeminds (as opposed to “lowminds”, who don’t contribute to your interests). Here’s the problem: so many of us, even those who are no longer teens or in college, live under the specter of “peer pressure”. We’re afraid we “won’t fit in” if we speak to the contrary. And especially if we dig something that’s popular, we’ll be subjected to redundant reminders like “Just because it’s popular doesn’t mean it’s good”. You need not get into wasteful word wars and endless debates about the merits of something. If you feel a certain other person or group repeatedly opposes what you care about and that’s regularly getting you down, then spend more time with people who do share your appreciation. The Internet is laden with all manner of subcultures and microcliques, so even if you’re geographically-challenged, it’s possible to find others you connect with.
Be a little more selfish. Selfishness isn't always a bad thing. Some people are prone to giving too much to others and not feeding themselves, so if this is you, you need to adjust. More importantly, you need to be strong before you can strengthen others. It’s true that in giving to others, you may experience a positive feedback loop of joy, but you need something to start that off. Feeling your own dreams are denied because you’re always supporting others? Let them know what you want to pursue, and if they’re quality people, they should come to collaborate on yours in-kind. Love flows both ways in the best relationships.
Adapt, evolve, iterate. Emotions come in cycles, and each time you go through feeling unloved, benefit from it. Go deep inside your head and familiarize yourself with why you feel this way, what triggers it, and when this is most likely to happen. By learning you, you’ll have better control over the cause-and-effect of your unhappiness. Extreme cases require medical treatment, but in the vast majority of instances, you have, or will adapt to have the power to do something substantial.
Writing in a journal. Even if it’s a few self-confessional paragraphs, it provides self-validation. Simply “getting it out” makes you feel better, and based on what I said above, don’t waste attention on those who don’t appreciate your bravery. Gravitate to those who do.
Don’t ever think “I’m not good enough” or “I don’t know enough”. Having struggled with pain, you’re good enough. Having experienced suffering, you know all about it. With all the talk about “believing in yourself”, that should never be taken in a vacuum. Each one of us is influenced in positive and negative ways by external forces, and our lives are never static. The balance is dynamic, our moods shifting by day, or even by hours. What we choose to expose ourselves to and participate in is a large deterministic factor on our world outlook, and this is especially true in an age where more people choose what news they’ll watch, not because it reports with objectivity, but because it tells them what they want to hear.
Ultimately, it’s initially hard to “pull yourself out” when you’re feeling kicked like a stray dog. But this is why I shared the above. There’ve been times where I was sure everyone hated me, but then I realized that this was just a temporal lie, my fallible emotions playing a nasty trick.
I hope that these words will guide you to a path of realization and solidifying the fact that people do care about you. The most important person amongst those people is none other than you!