Has anyone taken methergine?

I had a D&C on August 17. I went to the doctor on Thursday because on 2 different days I began passing large clots out of no where...no real bleeding otherwise. She confirmed that I still have clots that need to pass and put me on methergine for 3 days (3 pills each day). I've now taken 2 pills (last night and this morning) and haven't really noticed anything yet. Has anyone taken this? What was your experience like? Did it take a few doses to "kick in"? I'm just really hoping that this solves my problems and this can all be over!! TIA!!