Miscarriage, breastfeeding, pregnancy

So January 4th I had a miscarriage baby was only measuring 3 weeks 4 days. I bled for almost a week and my HCG levels were 5 a week later. Tomorrow marks 6 weeks and still no period I have taken 2 Dollar Tree tests both negative. I'm currently still breastfeeding my 19 month old. I wondering if that may play a toll on not getting my period back? My period is normally like clock work every month so I'm kinda stressing out.