it is most likely your belly stretching and making more room for baby . Braxton hicks will make your belly hard for a few seconds and then release, sometimes they can hurt really bad and other times just uncomfortable.
They are most likely real contractions. The is completely NORMAL unless you are getting them in a regular pattern. Your doc will probably start asking this week or next if you have had any. As I said it is very normal and is just your body getting ready.
the crampy feeling could lso be your ligaments stretching, the baby doesnt have much room left. ive been having similar feelings sometimes i think its BH and other times i dont.
im having the same and i think they are braxton hicks been hapening on and of for a while now it just feels very tight in side