What is happening in my stomach?

[QueenCeeHelp]

I've been experiencing excessive belching and flatulence for 2 months now. I am trying to figure it out and solve it myself. But I still need help from our respective gastroenterology doctors here. Everytime or mostly every after meal, I feel like my stomach is super full like its gonna explode. My upper abdomen is bloating.. became bigger. Then after 10 minutes, gas starts to come out.. (flatulence) coz gas has extreme foul odor.. after all the gas was out. My abdomen returns to its normal size. Another symptom, is when I wear quite tight jeans.. my abdomen becomes larger again.. and whenever I try to not make the gas out or should I say I try not to let my fart out. My stomach will begin to ache. The pain is uncomfortable that I really need to let go of the gas so I can feel at ease. Third, most of the time I have shortness of breath so I inhale deep through mouth. Please help. I don't know what medicine I should take. My bowel movement also changed..sometimes I feel like I have diarrhea.. but sometimes even if I want to poop. Its not coming out. I've search about the symptoms but there's a lot of disease or what that has similar symptoms. Sometimes I feel dizzy but just for about 4 seconds.. btw, I am plus-sized. I don't know. Help me please :(