First Day of Letrozole & Im Nervous

Sooo we've been ttc for baby #1 over a year now & I dont even wanna get into the number of negatives I've seen. GOOD NEWS IS: My periods have been coming on regularly(I have PCOS). I slowed up eating meat & exercised every other day. Im amazed with the results. Oh, and I took prenatal vitamins every other month( for bout 5 months)....well this is cycle day 3 & Im about to take the first letrozole pill😰 Im nervous ladies.....any tips? And when should I expect OV?