I have had stomach problems for the past 6 years, I have tried to see Doctors about it but I can't afford it, and it's starting to get extremely painful. I'm 20 years old now and think there might just be no hope for my tummy...

Everything I eat causes problems, upset stomach, gas, I have tried every diet there is, I have fasted, cleansed you name it. I
completely cut meat of of my diet 5 years ago and have been a Vegan for 2 but nothing helps.
I can't lose weight or gain it really, it just kind of sits in the same place. I don't know what to do.... I try to ignore it but it's gotten to the point of my not really even wanting to eat at all. Does anyone have any advice at all?