Castor oil..

So.. I took castor oil (2 table spoons with a glass of OJ). I've been drinking lots of water to stay hydrated. I've been monitoring babys movement and I have a doppler so I've even checked heartrate a couple times to make sure it's normal. Everything is just a little to fine though. I literally feel nothing no cramps no diarrhea no nausea and I took it at 545 so it's been about 4 hours. I know castor oil is frowned upon by many but if anyone else has tried it what was your experience I'm at a loss that its doing nothing at all.