31 Weeks Pregnant and my 2 year old jumped on my tummy?

You didn't hurt the baby at all. It may have caused your uterus to practice by giving you Braxton Hicks ...it does happen. And if they are not getting stronger and closer together, you are fine. If they do get sharper and closer together, call your doctor. They would want you to come in to get medication to attempt to stop labor. I will tell you though, it takes something like a car crash to start them. And I will also tell you when I was pregnant with my twins, I had labor pains (doctor confirmed they were real contractions, just never strong enough to deliver yet) for over a month. So people can have light contractions for a very long time with out actually going into REAL labor and delivering. Just moniter them and try and relax.