My bowel movements are very watery and I horrible abdominal pain and sometimes even vomit while using the bathroom my doc just said I was constipated?

Something very wrong. Watery stools is true diarrhea + severe abdominal pain + vomiting is an acute gastrointestinal problem that must be evaluated immediately, either in a doctor's office or an emergency department. If you are a young female, i would ask if you are purging (inducing bowel movements with laxatives), or inducing vomiting in some manner, as a means of losing weight. Whatever, get help.
See a gastroeneterol. See a gastroeneterologist you probably have an infection that needs treatment if it has not improved after 24 hours.