Hi. I noticed problems after even 25 lbs loss (had my surgery on 3-7-11). I was getting hiccups and felt nauseated at night. I have lost a lot of fullness in my face and went back to the company that handles my equipment. We did a 2 week trial with auto-pap to see if I could tolerate lower pressures. I was also fitted for a smaller mask. I went back yesterday for a download and was ok'd to go down on the pressure. I am back to cpap now, but just at a lower maximum pressure. Between that and the mask change, I am MUCH more comfortable. So, try contacting your equipment company and see what they can do for you. Hope it helps and good luck!