Unsure about ovulation can someone help?

We have been ttc for 3 months. I have been on chlomid, I ovulated the first month at Cd 24 ( I was late getting in) it was 22. I have been running a 34 day cycle. The second month I went in on Cd 21 and was only a 0.5. This month at Cd 21 I was at 15. So this is my big question. It shows I O'd. But.... Could have it already happened or could it be in the process of happening still. Since I do have a later cycle and the number was only 15?..... Thanks. I am hoping it just means I am done and peaked and it isn't just still climbing.