Ovulation Frustration

Hello! I am 32yo with a 4yo and trying for another. Does anybody know why I would test positive for LH (test same color as control) OCD 13, negative OCD 14, and then positive on OCD 15, and twice on CD 16? CM has been anywhere from thin and watery to stringy and thin. This is my first cycle TTC. I’ve been BD each day since Wed. I have been to OBGYN twice this week for ultrasound and they said most of my follicles need to grow more to ovulate but I had one that was nearing being large enough or it could be possible that one had already ovulated and burst thus they wouldn’t see it on there. Any input is appreciated. Thanks in advance. Good luck to all. Yes