What Causes Bloating Of Stomach And Indigestion?

Hi there. I am a 27 year old female. I am a vegetarian and have been for about 10 years and I am also active and fairly fit. I noticed about a year ago that sometimes (normally after a night of drinking) that my body would become swollen. Most noticably in my abdomen but also the fingers, feet, legs and even face. It didnt happen often and my body would return to normal after 1 or 2 days. A few months ago, it happened again but this time it was really only in my abdomen and it was persistant. I became bloated and it lasted for days, would go away for a few, then return with no real trigger. It has become so uncomfortable (and sometimes my stomach is quite sore but I think that is due to the muscles being pushed outward so far) that I am now on an elimination diet. I have be gluten and dairy free for almost 3 weeks now but with no real noticible changes. I have also mostly cut caffine out of my diet. I am also still quite regular. I started taking a probiotic made called Align which contains the bacterium strain Bifantis. I read that in studies it has shown to help reduce IBS or SIBO symptoms. I have only been taking this for about 5 days now though. I think that I have had almost every test done on me that can be and my doctor has recommended seeing a specialist but I was told that this could take several months. I have had blood tests which ruled out any infection causes like an ulcer or liver damage or celiacs or things like that. I also had a Barium Enema which came back saying everything was fine except that my intestine was a little redundant . I also had a ultrasound which ruled out any cancer or cysts. This problem is greatly affecting my way of life. I am losing confidence in myself and maybe even becoming a little depressed as I feel disgusting almost every day. Last week I had almost no bloating at all and was so excited but it ruled out alcohol as a trigger because I had had some drinks the evening before. Do you have any idea what this could possibly be? I have a feeling it is not a food intolerance. I think that for some reason my body has just stopped being able to properly digest food regardless of whether it is gluten or dairy or vegetables. Is this possible? If you have any ideas of what this might be or what more I can do I would greatly appreciate the advice. I truly cannot stand to be in this discomfort much longer and am willing to do or try anything!