How long does peak ovulation last?

I've been using the Clearblue Advanced kit and the last 4 days I got blinking smiley faces. Last night I thought I was ovulating (cramps, bloating) so I took another test and got the solid smiley face. I took another one this morning just to double check and I got a solid circle meaning low. We BD'd last night but I'm wondering why it dropped to quickly?  Or is that normal?