Clomid growth

After my miscarriage, the 50 mg of Clomid didn't work anymore, so I switched to 100 mg. At the initial scan, there was a cyst visible, but luckily it was gone by day 10. I'm now on day 16, and there's one egg measuring 12.5 mm. My doctor says there's still a chance it could still grow. Have you experienced this before? I don't have much faith in it myself and would prefer to move on to 150 mg if 100 mg clearly isn't working. It's making me feel a bit discouraged. Any experiences?