Crochet Curling

So I made it to round 13 or so and it started to curl up on me around the edges. The pattern was for a 5 inch circle and I hadn't thought about maybe needing to add some extra stitches in to keep it flat until now. Eek! I have to rip it back out a few rows until just before it started curling, after my two shell stitches I chain two right now and I am going to change that to chaining 3 between my shell stitches. Crossing fingers this works out! I hope to get to at least a 20 inch round doily, wish me luck!