Pre term labour signs.. help!

33 weeks tomorrow with my third pregnancy. Much different with this one than it was with my girls. Anyways I have the need to go to the bathroom every couple minutes. Little dribbles that feel like good relief afterwards. I make sure I sit there a little bit longer than usual to make sure bladder is fully empty. There is no uti. But with almost every trip to the bathroom I’ve been doing a bm which isn’t normal for me. I have ultrasound tomorrow but that’s just to see if his vsd is closed. And then Wednesday I go for my prenatal appointment. Oh and I have been drinking lots of water. Advice pls? I should also add that I’ve had 2 tightening of the stomach. (Braxton Hicks contractions)