Sorry you are going through such a hard time right now. Do you have any idea what is causing your depression? I noticed that you titled your post HIV...are you HIV+ or are you afraid that you might be?
I only ask becasue if you are afraid that you might be the best thing to do is go get tested. This way you would know one way or another and you could save yourself alot of worry.
Depression is hard to deal with but you can overcome it. I would suggest that you see a psychatrist. They are trained in helping people deal with and overcome anxiety and depression. It is possible that you might need to take an antidepressant. I don't know that for sure but a psychatrist would be able to help you with that.
Also, maybe you should try keeping a journal. That might help you with getting some of the feelings you have building up inside out. Make sure you are eating right, getting enough sleep and exercise.
Please know that you are not alone and you can get better...Hugs....
Good answer, mine sucked. lol