No ovulation round 2 of clomid?

Is it possible to ovulate on the first round of CLO (50mg) and not the second round of CLO (100mg)? Last round I ovulated on cd 18 and got positive opks on cd 16&17. This round, I am currently on cd 17 with no signs of ovulation. Could the higher dosage have done something to my body? Had a follicle scan on cd 13 and I had one dominant follicule (11mm). Could that follicle just stop growing and cause no ovulation? Feeling like this cycle is a failure. I was hoping to get my Christmas miracle this cycle…looks like it won’t be happening.