It's been like two weeks after my colonoscopy and I feel nauseous once in a while is that normal?

Not usual. Nausea should not be a part of the after effects of colonoscopy. I would suggest you call your doctor and discuss. Something else is going on. Depending on the findings at the time of the colonoscopy and whether you started on some medical therapy for those findings, the nausea may be related to that therapy. But if no therapy was initiated, this is an unrelated symptom after 2 weeks.