Hey there, I'm Peter. I know the feeling your having right now because I've had it too myself. You feel lonely and you feel like the whole universe is railing against you. Depression is a nightmare. It leaves you feeling drained all the time and you have absolutely no motivation to do anything and you really just feel like letting it all go. If you can I would really try to speak to someone about the feelings your having. I know you parents don't believe in psychologists or councillors so maybe you should go and see one without letting them know, but you should maybe try and talk to them about it first.
As I opened up to my parents about my depression I felt that they didn't fully understand what I was feeling and I found it hard to get my point across. I broke down crying and I managed to get all my feelings out there. That helped me in a big way to get all those feelings out there and I felt at last that my mother knew what I was going through.
Try doing some exercise as this can help to greatly reduce the symptoms of depression (anything that can get your heart rate up, even just a brisk walk) and try not to isolate yourself either. I felt worst when I spent a lot of time by myself in my bedroom. My heart goes out to memoi and I promise you that things will get better
Ur little friend from NI