Looking for info on follicle development

Hi there

I'm on my second cycle of letrozole and just had my first follicle scan done. I was told it's measuring smaller than they expected and the womb lining is thinner than they expected at day 10 but assured me everything was normal and asked me to repeat the scan in a couple of days.

I'm really worried it's going to fail again. Just looking for some info and positive experiences to ease my mind.

Thank you