Missed period - TTC while breastfeeding

Hi, I had a baby in November 2019 and have been breastfeeding since then, my period came back in June this year, it’s been a little irregular but only by 3-4 days tops but I haven’t had it since late October and no signs I’m beginning, I cramp a lot so I always know when I’m starting! We were starting to trying for baby #2, November was the first month skipping protection but I got two negative tests, one on the day of expected period and the second one I took when I was 5 days late so I’m pretty sure it’s not pregnancy 😅

Does anyone know what is going on or? I don’t see anything on google that says your period can stop if it’s already started while breastfeeding and I want to start trying for a baby 👶🏼 🍼 - I’m hoping to give birth next year hopefully and this is annoying me 🥺

Oh and I don’t breastfeed that much! Only 2-3 times a day and sometimes at night!

I’m 21 years old also if that matters haha