One month "stall"
You've lost a lot of weight in 2 months! Your body is just freaked out and adjusting. If you are getting all of your protein and water in and I'm sure your calories are pretty low - maybe too low? If you're doing everything you should, the weight loss will start back up. I've had lots of little stalls, it's frustrating, but be patient, ride it out, and stay off the scale for a while!
I'm 5 months out and just had a long stall (about 4 weeks) and was getting frustrated, too. I changed up my exercise and changed my eating to different types of protein - i was getting pretty set with the same food every day. It seemed to help. It also may have just been the time the stall was ready to quit! Good Luck - it is frustrating.
I don't think it's super common but I've certainly known at least a few people that have experienced it. I know it's frustrating. I think you should stick to your plan. Consult with your surgeon, or even better, a registered dietician, to make sure you're getting the nutrition you need. And try staying off the scale for a few weeks so you don't let it drive you nuts.
Please note: I AM NOT A DOCTOR. If you want medical advice, talk to your doctor. Whatever I post, there is probably some surgeon or other health care provider somewhere that disagrees with me. If you want to know what your surgeon thinks, then ask him or her. Check out my blog.