I dont think its right to feel that way.. basically you are already feeling guilty, but you want to let them have the blame instead to make yourself feel better. why? whats the difference? because your still be SA.. why are you trying to look for excuses?
why cant you just do something about it now? Family will always love their kids, no matter what happens. If you feel guilty, then its time to do something about it.
Its not going to be easy but it will work out if you believe in yourself. You just have to change and dont look back. Its how people become successful.
Its never too late to make a change, your be happier too.
There was this fat woman i saw on the newspaper, she lost alot of weight and she wrote a very inspiring quote, i dont remember her quote but its in her own words she said something like taking baby step. she said it in a very nice way, and when i read that i felt a light bulb lit up in my head. i think you need to find your motivation, it helps to make a change in life.