Unexplained weight loss

I feel stupid asking this because I know the answer pretty much. 
I'm 27 years old and I'm about 5"2. In October I was my heaviest at around 141. I was not comfortable with it but didn't do anything about it. Now in December I'm 115lbs and have no reasons for this weight loss. 
I keep dropping pounds and have no idea why. I'm not complaining I just know it's not healthy to loose that much weight in 2 months. 
I've been stressed out at work more then usual but I think this loss is too much to be put off as stress related. Any ideas/insight?