I am approaching this post from a different perspective. From what you write, you sound like you might have a condition called Irritible Bowel Syndrome (IBS).
No one really knows what causes IBS; the gut, however, has the largest concentration of neurons outside of the brain. It is not without reason that people feel nervousness and anxiety in their stomachs. And, that is due in part to that flight and fight reflex that we all have. It is postulated that in IBS, that interaction between brain and gut is VERY oversensitive. But no one really knows why IBS happens.
The main signs of IBS are abdominal pain OR discomfort that is relieved by or associated with a bowel movement. There also can be chronic dirrahea or constipation. Abdominal bloating can also occur, as can the feeling that you did not fully defacate when you emptied your bowels. Some people also report white mucous in the stool.
Some report that food and stress can trigger IBS symptoms. Your situation of spicy foods is a prime example. I would reccomend you keep a journal log of what you are doing and eating when you have IBS symptoms. Maybe in that way you could find some way to coorelate cause and effect and so learn to lessen the IBS.
In IBS, nothing wrong can be found in the intestines when they are examined, but clearly a problem exists.
Support groups can also help with emotional support...it can be therapeutic to talk with those who have your condition.
There are many medications that can be used for IBS...including some of the antidepressant medications, antispasmodic medications, and others. Prilosec and Nexium decrease stomach acid, and dont really affect the intestines. They are used more for heartburn and ulcer than they are for IBS.
I suggest a physician visit for diagnosis and evaluation and possible treatment. Here is the Mayo Clinics site on IBS: http://www.mayoclinic.com/health/irritable-bowel-syndrome/DS00106/DSECTION=1
I hope I was able to help you,