Not sure what’s going on HELP

So my husband and I have been trying for the past 2 months still nothing I know it takes time as I’m a mother to two beautiful little girls 1 and 4 however, back in June of this year we found out that we were pregnant but unfortunately the excitement ended in a miscarriage two days after we found out. So after the misscarriage I got back on track with my cycle now I’m still breastfeeding my one year old and I can’t seem to figure out if my nipples are sore because of her or if this is a sign I also, missed my period which was supposed to come on, on the 29th of Dec and today is the 30th and still no sign of my cycle HELP !!!!