Pains in my stomach - can you relate?

All my adult life (now 27) if I eat a large amount of carbohydrates (potato/rice/pasta) then I will have a serious bloated stomach which literately doubles in size. I did a test once before my meal I weighed myself and then afterwards and I had put on 7lbs in weight!! It's unbelievable. I have eating problems too where I do not stop and overeat and cause myself serious discomfort, not all the time but it is a problem. A few years ago a was taken to hospital with serious bloated stomach that wouldn't go down and the pain was awful. I was kept in for 9days, was fasted for 6 days and they did so many tests, they were unable to say what the problem was and just gave me acid tablets. Didn't really do much and just stayed in the medicine draw. But recently in the last few months I have had (what it seemed to be) extreme trapped wind. I have had 3-4 BAD episodes, so bad that I need to call out of hours doctor for advice, the pain was extraordinary. My doctor didn't want to investigate further, just told me to take Rennies!!! Is he mad or what>??? So I did what he said and just now today, been up all night in agony. Done all the home remedies, lying on the floor doing exercises, hot bath, hot drink, hot water bottle, three types of over the counter wind relief. But nothing stopped this pain at the top of my stomach; it’s all hard and hurts to press. I haven't slept and it's now nearly 6am and the pain started about 8pm last night. The out of hours doctor gave me a few Bascopan tablets until I get to see my GP this morning. I really would like more tests, I hate being like this. I know I am not the only one, but the pain is so bad it brings me to tears.