contractions 33 weeks pregnant ?

Yesterday I've started to feel like I keep getting this dull pain in my bottom on my back and it feels like I need a poo today I woke up went to the toilet about 4,5 times for a poo i know tmi sorry then my bum got really sore as I keep pushing to have a poo when I don't really need one it's this dull pain that makes me think that I'm now in bed it's 22:49 and still getting the same feeling but has gone more to period like cramps but less painful I'm 33 weeks and 3 days pregnant the pain ain't strong that's why I ain't gone in do you think I could be having preterm labour please I need some advice as I don't want to wake up my so to go hospital if it ain't nessesary