Gosh, I really shouldn't be giving you this tip because I became dependent on the darn thing but it really worked for me.

I was doing something similar to what you are doing when you swim. I think mine was a type panic breathing and I believe that I was taking a quick "sip" of air with my nose as it hit the water. So, I purchased a nose piece and it took care of the problem and two years later I was able to ditch it and swim on my own.

Hang in there...it will get easier!