Colonoscopy showed adenocarcinoma in situ from the 1.3 cm polyp that was removed ,what does that mean ? do i have cancer? what should i do next ?

Your doctor can help: The doctor who did your colonoscopy is supposed to see you after the polyp biopsy report has reached him. He/she can explain what you need to do now and in future. You have beginning of a cancer which has been removed right now. But follow up Colonoscopy should be done at the recommended intervals(at least every 5 years) to look for new polyps which are likely to develop /can lead to new cancer.