Hey sorry to hear you're feeling down again, but I know
exactly where you're at. I fought and struggled with depression for about 5 months before I finally decided to change my life around, lose some friends that were bringing me down, start working to rid myself of things that made me unhappy, and start allowing myself to feel joy. It had been almost 2 months since I had self harmed or felt super low and out of the blue I had a relapse, I felt awful and almost hurt myself again. I talked to a friend of mine who talked me out of it and reminded me of all the reasons I got over I in the first place and I felt much much better. Everyone has points like this where they fall back into low points of their life. I was so discouraged when I relapsed and I was just torn apart by the thought that I'd have to go through all the horrible and terrible feelings again. I felt like the weeks id been tearing myself out of it were all for waste.
Something that really helped me is like what Nal and Christabel said, I've gone through more journals in these last few months than you could imagine. It seriously helps, if you can't find someone to talk to (and I know, it really has to be a certain kind of person for you to open your feelings to) then writing out how you feel and what you're thinking is some amazing medicine. I would just write down all those things I wish I could cry about, don't try to make sense of your feelings, just let them out. It's a wonderful release of pain.
If you're not the writing kind of person, try just finding a quiet remote area and just talk out loud to yourself. Just complain about your feelings that you hate or don't understand and let yourself be sad. If you keep all your emotions trapped inside, it will not end up well, trust me. It starts to really hurt after a while.
I don't exactly know what else to say without knowing your situation, but just know that I understand exactly what you're going through. I know it hurts and I know it feels so very hopeless. I know it feels like you won't be able to make it through again but you can. And you will. Just think of all the things in your life that are important to you and live for them. Live for yourself and focus on the good things.
I am here to talk if you want, I'd really love to be able to help you through this, I know that having people who understand really helps. You can do it.