Sprintec question ? Normal?

Ok so I started This new Birth control ,I saw my mid wife at my 3week PP visit she suggested Sprintec which is the generic for Orthotricyclin . 

Well when I started it , I started go spot immediately, like the first week. The second week I've been bleeding like i have my period . I just started the the 3rd week and still bleeding heavily. I called my office and the nurse spoke to my midwife and she thinks its breakthrough bleeding . 

Has anyone experienced this ?? 

I'm sort of worried . I never had this happen before on birth control. 

Supposedly , I started taking it "to early" when I know for a fact I know my midwife said I could start taking it because I wasn't BF and it was OK.

Adding : I just had a baby on 11-9. I saw my midwife on 11-30.