Hi
Welcome to the MedHelp forum!
Chronic diarrhea that comes on and off can be due to due to parasitic infestations. Other causes are irritable bowel syndrome, celiac disease, Crohn’s disease, malabsorption syndromes, pancreatic diseases, diabetes, hyperthyroidism etc. If celiac, Crohn’s and other problems have been ruled out then lactose intolerance and IBS are the possibilities. Gas in stomach, burping, diarrhea all go in favor of IBS. Pancreatic enzyme disorders, liver dysfunction, HIV, cancer of the gut, and infections by parasites other than giardia can all cause persisting diarrhea. Lyme and lupus are other possibilities that present this way. Please discuss this with your doctor (GI doctor).
Since I cannot examine you and know other related conditions you may be having, nor is a detailed history possible on net, I have listed the various possibilities that should be looked into. Please consult your PCP for primary examination followed by proper referral.
Take care!
Might be time for a colonoscopy
and also I forgot to include, this has been going on since I was about 12, I am now 19