I didn't notice any difference in supply, either, though my midwife told me that if anything, the hormones in the mini-pill are more likely to cause an INCREASE instead of a decrease.
I know I am the odd-woman-out, but I did experience a drop about a week after starting the mini pill. My supply was borderline for twins to begin with though.
Good luck!
BFP#1 12/18/10 EDD 8/28/11 | 2/14/11 discovered that our baby girl had anencephaly D&C 2/17/11 at 12.5 weeks | no O or AF post loss - Dx: AO + mild PCOS = secondary infertility Provera after 70 days = AF but no O | Provera + 50mg Clomid after 110 days = AF but no O 3 rounds of 100mg Clomid + Estrogen + Progesterone = mixed O results, all BFN hysteroscopy 1/6/12 - removed fibroid tissue injection cycle #1 - 75 IU follistim + ovidrel (triggered 2/9/12) + endometrin = BFP!
EDD 11/3/12 | Beta @ 13dpo = 184, 17dpo = 993, 26dpo = >5000
IT'S TWIN BOYS!! Tommy and Charlie arrived on 9/10/12 after less than 6 hours of labor at 32 weeks
Re: breastfeeding and mini pill...
I EPed and didn't notice any difference in my supply when I started the mini pill. I hope you have the same experience.
BFP #1 9-22-10 Missed M/c 10-18-10 D&E 10-28-10
BFP #2 5-9-11 EDD 1-12-12 Audrey Rachel born 1-12-12
BFP #3 9-21-13 EDD 5-30-14

Good luck!