Has anybody had in success in getting pregnant on the actual day they ovulated (but not having had sex in the lead up to ovulation)?

We missed the few days before this month, but managed to dtd on the actual day. Am a bit confused by the fact that my opk was negative the night before I ovulated (I thought it was suppossed to tell you 24 hours in advance?), but my chart showed that I ovulated the next day and also got a positive opk that day. Just wondering what our chances are...

Any positive stories would give me hope!