It was just strain on the ligaments in your abdomen. Happens to me with all three of my pregnancies.
Actually, that happened to me one time when I sneezed at a weird angle. Don't stress. It was just a shock to the area. If it still hurts tomorrow, or there is bleeding, then worry. It felt like mine was bruised for a little while after, but my baby is fine 15 weeks later.
go to the hospital n see wats wrong. u dnt wanna risk nothing