Early ovulation on clomid?

[Molly123456]

I am on my third round of clomid, and today is cycle day nine and I took an opk and it came back positive. It just seems early in the cycle to be ovulating. I took the clomid cycle days 3-7 and my cycle averages 29-30 days. Anyone else ovulate early? Last month I didn't use the opks because I was on vacation and accidentally left them at home so I am not sure when I ovulated. I know I did though because my cd21 blood test results were 41.7.