I would say do not use it because its dangerous to your baby but since you did I would call your doctor asap and get their advice.
I'm 39 weeks. I took it like 2 hours ago. And nothing at all. A little tighting of the tummy but other than that nothing.
Hiw far along are you? Castor oil is effective only when you are far enough along (39/40 weeks best use I believe?) As it can be a very harsh way to induce labor at home if the baby isn't ready. I've noticed a few posts on here recently (and then asked my midwife if it was safe to use), that some women used it and had terrible results - constant diarrhea, cramping, vomiting for hours and dehydration. My midwife said it was likely used too early, as the way it works is that it irritates and engages the colon and intestines (vomiting, diahhrea) which then can bring on contractions if far enough along. For me personally, I would use it ad a last resort. Labour is ugly enough without starting it on the toilet hun!