Help - PP

How soon after birth can you possibly get pregnant? I'm not asking so I can try and get pregnant... But I've feeling different the past couple of weeks and don't know if it's normal for postpartum, if it's my period about to return or if it's early pregnancy signs... I am breastfeeding and I've heard that helps but isn't 100%. But I also know you're super fertile.. I had started on the mini pill but I know it takes a while to become effective and we did have sex a few times when I first started it. Lately I've heard from soo many moms that got pregnant within the first few months and so I just wasn't sure really how soon it can happen. Any ideas or any experiences with this?