Alternating diahrrea & constipation, indigestion/heartburn at night, & occasional rectal bleeding when feel like i need to go, & weight gain.

Possible: Ibs with hemorrhoid or ibd or fecal impaction need GI evaluation.

Check food you eat: Depending on how long you've had these symptoms, it's best to have food allergy panel done to check what you may be allergic to, especially wheat (gmo) ; gliadase, as these can wreak havoc in the gut lining to the point of causing inflammatory symptoms.This can be done with a cyrex lab panel, or similar, and you may need to change your diet to a more bland, non gmo, organic based diet until then.