I Started Cutting A Couple Months Ago

I'm 16 and have been depressed for a while... I just have a lot of family stuff, my dads paralyzed, moms a drug addict, obviously divorced... My stepmom hates me and lets me know every day... My dad calls me fat pretty often and I go through fazes where I won't eat for a while and ill drop 15 pounds or so pretty quickly then something will happen and ill get depressed and start gaining weight again.. The few guys i've ever liked have shut me out of their life or used me and once i gave them.. what they wanted.. they left. Anyway I started cutting with a razor.. I don't even know what made me start I guess I just always thought about it and one day when I was bored and depressed just took apart a razor and accidentally sliced my thumb in the process and just watched the blood flow.. I feel pretty fu cked up about it.. No ones noticed. Im with my best friend a LOT though so i feel like its only a matter of time.. The other day I was jokingly trying to honk her car horn at a teacher in the parking lot and she was grabbing my arms trying to stop me and we were laughing pretty hard I didn't realize my sleeve had come up and she scratched one of my cuts so I realized they were completely visible I immediately pulled my arms back and put my sleeve over the cuts and stopped laughing. She apologized and said she scratched me. I could feel blood starting to soak into my sleeve.. I just said it was fine but I had to go and got out of the car and left. I was so scared. Until then I hadnt realized how scared I am for people to notice. If it gets out.. My friends will think I'm so fu cked up.. which I am i guess... I don't even know whats going on with me. I just know I hate myself and I feel better when I cut.