PP period?

S🌷 • Mummy to my handsome son and beautiful daughter 🐻🦄

I’ll be 14 weeks PP on Saturday and still haven’t had my period. I did combination feeding up to 11 weeks so haven’t breastfed for almost 3 weeks now. I took a pregnancy test and it was negative. Anyone else gone this long without a period? My son is nearly 3 so I can’t remember when I got my period after him. I don’t want to waste a doctor’s time if it’s normal but I am starting to get a little concerned!