You need to:
Get out of the house and SEE YOUR FRIENDS!
If anyone can give you the support and encouragement you need, it's the people you love and trust. Social isolation is dangerous in its own way, and spending all your time focusing on your weight rather than allowing yourself to have fun and live your life is just going to make things worse.
Look into therapy if you're feeling suicidal. I know you don't want to hear it, but talking does
help if you find someone willing and able to listen. This is coming from someone formally suicidal with therapy as a big contributor to my recovery, so please trust me when I say this.
Talk to your doctor about your weight concerns. Crash dieting is extremely bad for you and it's too easy to just gain the weight right back. Your doctor can help you figure out a steady diet and exercise program that will allow you to lose weight at a healthy rate and make it easier for you to maintain your weight once you get where you want to be.
For the love of Pete, don't deny yourself masturbation. If it's something you enjoy doing, cutting it out entirely will only make you more miserable. Self-denial is yet another unhealthy behavior.
Try looking into hotlines or online support groups, so that you can have someone to talk to at any time.
Truly, you're going about this in the worst way possible, and it makes me worry tremendously. While all of us here at Eden are happy to provide emotional support and advice, there's really not much else we can do. I know it's hard to reach out, really I do, but you're not going to get better or reach your ideal weight by shutting yourself away.