The pill...

Okay so I'm 21 years old, we recently had a miscarriage and since the pregnancy wasn't exactly planned we decided to wait a while before trying. So anyway, my doctor put me on a low dose monthly pill. I've been on it now for one week and 2 days and the last few days I've been having spotting and full on bleeding since the stop of my period. The cramps range from dull to sharp and intense at times. My boobs are killing me and I have absolutely no sex drive whatsoever. Is this common? Can someone tell me if I should stop and talk to my doctor or if I just need to wait it out.. I'm going crazy.