Over the last 24 hours (maybe 36) I have had really strong pains & pressure all through my back passage... sorry about TMI but is this normal? I dont necessarily feel like i 'need to go' but it does hurt & feel uncomfortable. Is this just a by-product of back contractions? (which I have started to get frequently)

If I go to the loo to empty my bladder, while this is happening, I unexpectedly get massive 'rolling pain' all through my pelvis & lower back.
I feel like either my water is going to burst at any second or I'm going to 'deliver the baby' & this is not bowel related.... just an agitated bladder.

Being my first time I just really have no idea... any thoughts or advice is appreciated.