Bloating confusion..mystery symptom?

Problem with this is I can't list my whole health history. But, I'm 19, I'm at a healthy weight, eat my fruits and veggies, cutting out meat, 8 glasses of water a day, excerise..

Anyway, my digestion has always been weird, and during the day I get this..bloat. I'll wake up and my stomach is flat, but as the day goes on it gets puffy. Then I wake up the next morning and it's flat again? When I get enough fiber it cuts it down a lot but it's still..there. Any idea what this could be a symptom of? Should I do a liver flush? Never done anything like that before, kind of nervous to, but I really need some advice in case this is a sign of something more serious down the line.

Thank you!