Femara/Letrozole

Terra • Married to my Mr. Right. Mom to my IVF heart warrior daughter born November 16, 2017.
This is the first cycle I'm trying Femara. My fertility Dr. Told me to take it cycle days 3-7 today is cycle day 5 my period is basically done just a little spotting. I'm having some cramping and pain though in my lower abdomen. Has anyone had this. Is it a good sign. I tried clomid 3 cycles and nothing happened not like this. I haven't ovulated in my own in almost a year so I don't know what it feels like. It's also to early for ovulation. Any idea what this may be? Is it a good sign?