Clomid Not Working

Stephanie
Has anyone else not ovulated using Clomid. My doctor has me on 150mg this month. We have used it for 5 months. I am not getting a single positive ovulation test. My cycle is usually between 28-29 days long. I started testing on CD 8. We are now on CD 18 and nothing. I am so frustrated. Anyone else had an issue and what did you switch to?