What is wrong with me? I'm depressed and feel like i could snap any minute.?

For the dizziness and haze... I think maybe you should eat a little bit more, as for the cutting just think of the awesome things in your life and don't dwell on the shitty things. Nightmares idk but try getting more sleep, the things you put in the back of your head go un noticed exept 9/10 that is what you will dream or have nightmares about. Good luck, and definatly talk to a parent or adult about it not friends as much