Hi I'm 24 and yes currently sexually active with one partner. It is 3 weeks before my next period and I've been having slight discomfort in my uterus area pain like minor menstrual cramps which has also caused a thin clear (sometimes pink) discharge for 3 days.Should I be worried? What could this be?

What sort of birth control are you using? Are you trying to get pregnant?

The problem is that minor cramps in that region can be caused by many different factors. You know your body better than anyone so you know if it is positively uterine or if it could be intestinal or what not. Regardless this is something that you should follow up with your OB/GYN. I believe pinkish vaginal discharge is reasonably normal, just indicative of changing hormones.