Try more Epsom Salts if you haven't already.
Other alternatives are a strong cup of coffee if you are not accustomed to drinking coffee or Good quality chocolate if you are not used to eating chocolate.
I made the mistake of drinking a cup of Columbian coffee sweetened with honey in the hospital cafeteria after some blood tests. I had a two mile walk home and while I was fortunately alone this was still a very embarrassing event for me.
If you feel any nausea at all it usually means there are either stones still trying to get out and/or toxins in your colon. Very important to get these out ASAP.
I had no stones after my first flush for two days. Then every two days after for about two weeks. Quite bizzare I thought.