Fibroids and birth control.

So I have a 2cm fundal fibroid. It was found through a transvaginal ultrasound because I was having some spotting between periods and one really heavy period. My OBGYN said besides the fibroid, my ultrasound was normal. She said if the spotting continued, that I should try going on birth control. I have been on birth control now for about 2 weeks now and I am still having some spotting and cramping. Has anyone else experienced this?

(Also did have a PAP and that came back normal too).