2nd IUI

Went for my day 10 ultrasound to check follicles and already at 18mm .... Last month we did trigger on day 14 and IUI day 16.... They told me to trigger tomorrow night and then Monday morning IUI but I wasn't expecting this so soon 🙃 also they want me to start taking estrace pills today 2 times daily until I find out if I'm pregnant or not since my lining in a little thinner still... This is a first taking this medicine and was wondering if anyone has taken them before and what to expect with them. More nervous this time around because the first failed and we only have 3 tries until IVF (which my insurance does not cover at all) dealing with male infertility