Nausea, black stool, heartburn, gas, what's wrong?

When I was about 17 I started experiencing serious stomach issues and finally just after my 21st had surgery for it. Hiatal Hernia, gallbladder removed, and the acid reflux surgery. It was an awful procedure for me and completely life changing. I still have issues to this day and am now 26. But I am starting to get symptoms again. Bloated & gas in my intestines, diarrhea, dark stools, severe stomach pain (when stressed), and lately nausea especially if I have something that is sweet. Even if it is just a breakfast bar or post workout shake.

Oh I am also a female, not overweight and excersize 3-4 times a week and eat virtually no bread products. I take Pepcid Max 1x daily and a probiotic, which has helped tremendously for keeping digestively normal it just does nothing for the gas issue that I get afternoon - evening.