33 weeks and having very dull period like cramps

Hi all! I was just at the obgyn yesterday. Everything went well. Later that night I had some period like cramping in my lower back. I drank a glass of water and took two tylenol. It went away after a little while . This morning now I have very dull period like cramps in my lower abdomen . Baby is moving around like usual at this time.  Is this normal at this stage of pregnancy or could it be a sign I might go into labor early? Should I drink more water and take another tylenol and see if it goes away again?