Suggest Treatment For Feeling Of Vomiting After Eating

So for the past four months. i would feel like everytime i eat i would get sick or just random times i felt like i needed to throw up and i did. so i had an endoscopy done and there was nothing wrong with my tummy. i'm 23 years old and i'm very worried that sometime else is wrong. the doctor said i just needed to go number 2 more so now i have been eatting more healthy and getting a lot of fiber in my diet because i'm all backed up. so it has been going good for awhile. until two weeks ago i reliezed that when i eat there is a certain point i have to stop because i feel like i'm going to throw up. and i used to eat a lot and now i can barley eat at all. i'm afraid to eat too much because i feel like its going to come right back up. i think i should get a colonoscopy to make sure there is no blockage. i have been trying to go to the bathroom everyday and i do but its like i have to force it out and drink a lot of stuff that has fiber. i just don't think that's healthy and there is something else wrong. please help.