I need to sleep

Patient: Four the last 4 months I have been having a very hard time at night with sleep. And I am confused about it. when I go to be I am fine but about an hour into my sleep I start a comstant cough and it get to the point of a foam vomit. I have gotten to the point I will sleep sitting up but still is not getting a full night sleep. I have tried a type of allergy med thinking that that might help it does not and just makes sleep worse.. Please help me.. Also I did have lap bang surgery in December of last year with no problems and a sucess of loss of over 70 lbs with a steady loss

Doctor: