Mid cycle bleeding

Can anyone explain this to me? So it appears that the beginning of February I had some mid cycle bleeding. Before and including my last period in January, my cycle was pretty regular. I've had mid cycle bleeding before off and on since i had my 4th child a year ago but my period always showed up on time. Now it shows I'm a few days late. Is it possible that the mid cycle bleeding was actually a second period? When is my period actually supposed to start?