I'm sorry Miriam, I can't help you as I don't make my own fondant. Perhaps another member has some ideas?
Maybe try a new recipe...I use 2 lb marshmallow, 3 tblsp water, and a little less than 2 lbs confectioners sugar. Melt marshmallows in microwave 2 min, in 30 second intervals, stirring between each. (add color before adding sugar)Then add sugar gradually until you can handle it with your hand to knead until smooth. Place in plastic baggie for later use. I find it handles better if it sits for a day or 2. When I need it, I soften it in the microwave for 15-30 seconds, and roll it out with cornstarch to prevent sticking. I hope this helps. My fondant last for months.