You don't have to BD within 24 hours to get pregnant, definitely not. The three days before and the day of O are the days you want to aim for, and remember that the sperm survive for up to 5 days so they are just hanging out, waiting for that egg!
FF says once your temp goes up you are no longer fertile, but I think if you can BD the day after O that probably isn't a bad idea either. The egg survives up to 24 hrs and you don't really know exactly down to hour when it happened so it can't hurt.
Anyway, my point being if you did O on CD17, you caught 3 of those 4 important days - which equals GREAT timing!
Hope your temp jumps up again tomorrow!!