Cramping on Femara/Letrozole

Ryan • PCOS. Hypothyroidism. FTM. 2nd set of twins. 🌈💙💖 Baby Ellen and James arriving on Oct. 2nd!!
Has anyone experienced really bad cramping on Femara? I've start my 2nd round of it today and my doctor upped my dosage to 5mg. My period was really light before I took it this morning and now my flow is very heavy and I'm cramping so bad it hurts to breathe. Is this normal?