A.J.
if they are on the sides of your belly, it's probably just muscle cramps from your stretching belly and added weight. make sure you are drinking plenty of water, not over-using your muscles, and getting the right mix of vitamins/minerals (sometimes muscle cramps can be from lack of potassium).
if you are having vaginal cramps, I'd make them check it out further, just to be sure it's nothing.
Braxton-Hicks contractions can start around your 7th month I believe. they can be very mild and almost unnoticeable or they can feel like the early stages of labor (but they are irregular, unlike "real" contractions)
hope this helps! and congrats =)