Has anyone experienced bad period like cramping in the middle of the night? I am 31 weeks and this…

Has anyone experienced bad period like cramping in the middle of the night? I am 31 weeks and this is the third night in the last two weeks that this has happened. It's pretty painful. I talked to my dr after the first two times it happened and she said maybe my bladder was full. Umm..I know when my bladder is full lol I pee constantly. Especially at night. This pain comes and lasts over an hour at least. Just wondering if anyone else has had this. Thanks ladies! Hope everyone is feeling well!!!