I had back labour, 36 horrible hours of it. My contractions were really long too, lasted a few minutes each time (grrrr!!!) I still haven't forgotten it 6 months later. But I didn't have consistent pain, it started in the small of my back + quickly spread out till my whole lower back felt like it was breaking, lasted a few minutes but then let go suddenly + gave me some peace and relief before it started all over again. If this starts happening to you it could be the start of back labour but if you're really worried, go in to be checked, they'll send you home again if its not.