That 'spike' was still within your "pre-O" range - it was above the temps for the day before, but not really above your other temps.
Just keep temping, having sex, checking CM, and anything else you plan to do. You'll probably be Oing within the next 24 - 36 hours.
Feel free to take a look at my charts. I often have a temp dip a couple of days before I O.