Contractions?????

This has probably been posted several times on here. Idk how contractions are supposed to feel. are they just braxton hicks but last longer? I think I'm having early contractions right now but I have no idea, it's a little painful. I've been trying to get comfy in bed for the past hour but my back isnt letting me at all and i feel this weird pressure pain type of thing in my lower tummy that cones and goes, kind of like i have to go #2 but I don't. I'm not even sure where or when to start timing? I am 38w+4.