baby movement stopped at 17 weeks??

Last week I was laying on the couch and my 15 month old came up and sat next to me then all of a sudden he threw himself back and hit my stomach with his head right where baby is positioned... it did hurt and sent a sharp pain through my uterus, the baby did move a little bit just after my son hit me but i haven't felt any movement from baby since it happened should i be concerned? I have a midwife appointment on friday but i also went to see her early last week (before the head butting ordeal) for sharp painful contractions in my back and she gave me a a quick ultrasound to check things over and he was moving around and jumping (i could feel him than and have felt movement since 9 weeks) I'm trying not to worry but i keep having the thought of a missed misscarrige pop up in my head every now and then and this is making me start to stress!! Can someone please help me???