I just turned 33 weeks yesterday and i had my doc app yesterday as well. The reason i'm worry is that last night i kept waking up with bad cramps in lower abdomen and lower back. I haven't told anyone because i tend to over react to pain its just the pain feels like its getting worst.
You need to call your OB or go into the ER.
call your ob or your l&d either one will put you on a machine to see if your contracting