Oh, you don't need to be sorry. Seriously. It is not your fault- you have done nothing to deserve these sad feelings, so acknowledge them, they are real and you are being heard and I am sorry that you are feeling so sad.

I have been where you are, and this I know: these feelings will pass. It doesn't mean they won't come back, but right now just get through them, to the other side. Maybe it means posting more, or talking to a friend, or taking a walk or just simply going to sleep to wait it out. It will subside I promise. Well, maybe I shouldn't promise, but I think I can say that time will help.