TTC after feeding, can anyone help?

Hi, I have recently stopped feeding my 8mth old. I had a period 6weeks ago and none since. I bought a saliva microscope to see if i was ovulating and it showed ferns(which should mean ovulation) for the last 7 days. I was wondering if anyone has been in a similar situation with trying to regulate their periods after feeding and I was wondering if i could get pregnant before my next period does come?? I am usually a 28 day cycle girl but have no idea when i am ovulating now. All OPK shows neg. I took a prego test a week ago and it was neg. Please someone help???