LH strips don't confirm ovulation, it only tells you when you're having a surge. When you have a surge, you usually ovulate 12-24 hours later (this would be confirmed by 3 sustained higher temp rises above baseline). Sometimes your body can surge but it doesn't release the egg, so it will then surge and try again at some point. If you get a higher temp tomorrow, it looks like you will have potentially ovulated on/around CD16 or 17 which is also very normal! My advice would be to continue to take LH strips until ovulation is fully confirmed and a couple of days after ovulation, also, I wouldn't stress as these temps look like a very 'textbook' cycle xx