It's a great relief isn't it? One of my dr's said sarcastically he noticed how all his patients didn't start to get better until after they got their SSDI! It's so much extra stress. I'm of the opinion that they try to wear you out and figure you're so sick you'll stop fighting. They obviously didn't know me very well.
OTOH, I was eligible for Medicare as they back dated me to original application date, plus I had gotten 2 raises before I even got my first check. If you had to get an attorney involved they might hold back some money for the fees, but they will send you a letter about it. My back check was 3 years worth, just about replaced all the $ we spent out of savings.