The baby is protected. I got in a car accident that totaled my car and the doctor said everything is fine and baby is healthy. It's been about a month since the accident and I've had a couple of check ups (on baby) since then and everything is fine. So your baby should be fine. I also run into doors a lot (belly hits the door first since it sticks out lol) and nothing is wrong with baby at this point and the OB says it's fine.
The baby is well protected in your placenta. You should only be concerned if you've had any pains or discomfort since you were bumped on your tummy.