What does this mean?

On Friday (Day 7 of cycle) I had a scan that showed a 11mm follicle. I was re-scanned today (Day10) and the follicle remained the same size. It didn't grow. I don't understand why this has happened. I have had this happen to me a few times now. It looks this my first IVF cycle will be cancelled. I'm going for another scan on Wednesday, to see it has improved. Has this happened to anyone and if so what was done to improve your situation. My FS has mentioned that she might put me on a small dose of puregon injections.