3-7 or 5-9?

Maggie • 30- Happily Married. Diagnosed with PCOS at age 19.
Ok, so a little backstory. I have done two rounds of Clomid days 3-7. I did ovulate both times but did not conceive. AF showed today so I asked my doctor if I should switch to days 5-9. He said the days don't make much difference so I could try it if I wanted. Has anyone had better luck switching days? Any advice would be so appreciated.