It's possible but unlikely in this scenario...wait 2 weeks and take a test to be sure, but I think you're ok. did they put you on the mini-pill since you're breastfeeding? I'd go ahead and start that sooner than later.
Also tell your hubby when he pulls out with a condom to reach down and wrap his fingers around the top of the condom so when he pulls out it doesn't slide off; my husband learned this trick the hard way too, lol.
I wouldn't worry about it.
probably highly unlike considering your exclusively b/feeding, your usually safe for 3 months but dont presume that it will take as long this time, it may but the more babies I've had the shorter time its taken for my period to return