Follicle size

I’m day 6 in my first IUI cycle. Had an ultrasound and blood work done this morning. I have my two largest follicles were measuring at 8.5 and 8.7 and the doctor said supposedly I still need more time. I have tonight and tomorrow night left of my letrezole meds to take, but since I am still measuring on the smaller side, I’m wondering if the doctor is going to put me on something else in the meantime? Has anyone else been in the similar situation?

Thanks 😊