Late period...

Currently, I'm 4 days late for my period, which doesn't normally happen. I have 2 babies already, the youngest is almost 6 months old and I've 4 periods already since he was born, 3 of them have come regularly and on schedule. The only times I haven't been on time have been when I get pregnant, so I'm freaking out a little bit lol. My husband and I haven't really been as active as we normally are, but we have had sex a few times (pull out method, which is new for us since having the baby, but it hasn't been the cleanest execution). Also, I've been like overly emotional for the past few days, like crying over videos of cute little fluffy animals. Please help!