Positive opk question

Ladies, can i still get a positive opk and ovulate with a small follicle? Im not sure if my follicle grew since monday. I had an ultrasound and i had a small follicle at 13mm just was still growing: i had another follicle ultrasound this morning and no measurements were giving to me. So im confused. Im waiting for my doctor to tell me my results. But i had a very good uterine linning and will be going on progesterone tomorrow night 💕 crossing fingers for my rainbow baby 🤞🏽🌈💕