Letrozole/Femara

This is my 2 round of taking femara. The 1st round I did not have a positive ovulation but instead I bled after working out one afternoon. For my 2nd round I’ve been bleeding for almost a week now. Heavy enough for a tampon but it’s slowly tampering off. Period is not due for another 2 weeks.

What could possibly be going wrong and why is my body not responding to the medication? :(