Symptoms: bloating, sharp left pelvic pain, nausea, diarrhea, constipation. what could this be?

Pelvic pain: Many different things can give you those symptoms. Diverticulitis, colitis, colon polyps, adhesions/obstruction, ovarian cysts, less likely cancers can all give you left pelvic pains. If this is recurrent or has lasted more than a couple days i would see a surgeon or gynecologist asap. They will be able to examine, take a good history, obtain images or obtain a colonoscopy that will help.