Hang in there! You can come back from this with patience and a commitment to your PT exercises.
In '06, I suffered a total tear of the supraspinatus and had surgery to re-attach it. I spent about 6 weeks in a motorized chair that raised my arm up & down to improve my ROM. After about 9 months of PT, I was given the OK to begin lifting and started with a tuna can! It was painstaking slow and it took over a year to get back what I lost but after 2 rounds of STS & P90X, I am now lifting heavier than pre-injury, doing full pushups, pullups etc.. I still have some grinding and occasional pinching of scar tissue in that shoulder which I'll have to live with but I'm as close to 100% as I'll ever be.