Castor oil doesn't induce labor it's a laxative so all it does is make you have the poos and having the poos that bad is what can put u into labor but I agree castor is a very bad idea.
Our midwife actually warned us about this. Castor Oil is an outdated method to try and induce labor.... Many times having the effects you described. Hope you feel better soon, and drink lots of water to replace your liquids.