1st round Clomid, positive opk, NO FOLLICLES?!?!

[mod19]

So I already ovulate on my own but only have one tube so my Dr prescribed me clomid. I took it cd5-9 and went in yesterday on cd16 for a sono. I usually o on cd19-20. Yesterday morning a few hours before my appointment I got a positive opk, so I expected to go in and see some eggs ready to go...but there weren't!!! There was one little one my Dr said wasn't close to being ready. So what gives? Why did I have a positive opk with no eggs? Its so frustrating and confusing. The one little one that was there was on my left side, which is the side I need them to be on. I usually have positive opks for about 5-7 days and I'm not sure which of those days I ovulate. Is it possible I released the egg before the sono was performed? Or is my body just not liking the clomid. My Dr is upping my dosage to 100mg for next cycle.

 

[mod19]

I would like to add that I know I ovulate from blood work. I used to temp but since we've been TTC for 4 years I'm over it and have stopped all that.