Horse head butt my stomach!!

I took my son to s petting zoo. The animals aren't free but the gates are very low so you can touch all the animals. We were petting the horse and he head butt my tummy very hard it almost knocked me over!! It did hurt but eventually went away. I didn't feel my little one move for about 4 hours and she usually very active especially when I eat... I've felt little movements here and there now. Should I still call my dr. or just relax. I'm so worried the horse hurt baby, it hurts where you touch where he hit my tummy.