Ahhh sabar ye, first pregnancy memang confusing! Honestly, slipped disc pain and contractions are quite different, kontraksi usually starts from front belly and wraps around, sedangkan slipped disc tu more like sharp, localized back/nerve pain that doesn't really tighten your whole belly, you know? The cramping and sharp pain at your pelvic area plus frequent toilet trips at 36 weeks is actually quite normal (baby pressing down!), tapi since you have a history of slipped disc, I'd really suggest you mention this to your doctor or midwife at your next visit so they can properly check what's going on and rule out anything serious. A few of my mum friends with back issues had similar worries near the end, and the doctor was able to confirm whether it was pregnancy discomfort or their existing condition acting up. Better safe than sorry at this stage, mama!