Is this the start of labour? I’m 33 weeks

Past 2 days I’ve had an upset stomach, all of last night it felt like a ton of pressure in my vagina and the bottom of my back.

I had a bath last night and after I dried myself off, I felt a little trickle but wasn’t sure if it was from the bath or if it was my waters. I put a pad on and can’t tell.

It’s now 2pm and I can’t sit down properly, every time I get up or sit down, it hurts so much!! It feels like I need to push a poo out but I don’t.

Can someone help me?! (Also it’s not pain from upset stomach)