Femara, 2 daya late from af

Hi all! I wish i was here to give pregnancy results but im not...😔 im two days late from my period and I'm never late. I always have a 28 day cycle. I took letrozole this month. I have no signs my period is coming, took a test, completely negative. My doctor office said wait til Friday and give them a call back. I had a miscarriage Jan 2018, and still TTC since then. I had every test done, my husband has been tested, and everything is completely normal. Need advice!