Sex drive

I had my baby boy Samuel on December 28th, 2016. He's now 6 weeks and 1 day and my sex drive is going wild. Since 4weeks.... maybe it's the fact I'm feeling good about myself. I'm down a size from what I was before I was even pregnant... Hubby and I have done it unprotected 3 times in the last week. No form of contraceptive at all, not even pulling out. I've been breastfeeding and formula feeding. So nervous I'll end up pregnant again. Dont get me wrong, i wouldnt mind being pregnant again. Ive had major infertility issues, so it might be for the best anyways... Anyone else feeling this way? Or nervous they'll end up pregnant right away again?