So sorry you feel that way. I have ups and downs but I think for me it's more of a dip than a depression because I don't get that much carried away into it.
And it's not so much loneliness I'm feeling but also not being happy with the way I look (I mean, my body) and the most frustrating thing about that is that a lot of people think that I'm overreacting. Because I am underweight, skinny, instead of overweight, people think it's not right that I'm not satisfied with that and that I should get over myself, in addition, I get a lot of comments "omg you're so skinny" "do you even eat", they don't understand that saying that is actually rude, also they don't understand that being underweight can has as much problems as being overweight (not finding right clothing, health issues etc.) and besides that it is technically even harder to gain weight than to lose weight and it goes a lot slower.
Anyway, I just want you to know that there is always someone who cares and who you can talk to, because you are definetely not alone and please don't give up hope!