D.B.
This is impossible for us to diagnose - there are a lot of organs in the abdomen - uterus, ovaries, colon, small intestine - don't wait any longer. It's obviously not a temporary thing relieved by ibuprofen so call right now and be seen by your primary or your OB/GYN. It's Friday and I don't think you should go through another weekend. Don't fool around with this. Your body is telling you something.