late because of estrogen or am I pregnant?

A
Has Estrace messed anyone's else's cycle up? 
Completed 3rd <a href="https://glowing.com/glow-fertility-program">IUI</a> and was prescribed 4mg daily Estrace vaginally to build lining for the next 18 days unless AF comes, which she hasn't. I test tomorrow, hoping no AF because I'm pregnant. But if I'm not...I'm guessing the estrogen hormone messed me up?