Early period while in pill

Alright , my SO and I had sex last week on Saturday . He had cum in me but I am on the pill and have been for a year and around 2 months now . When he had cum in me I still had a week before my period starts . It's now 2 days before I start my sugar pills to start my cycle but I started bleeding today . 2 weeks before he had also cum in me on a Friday . Mind I don't get my period for 3 months at a time because that's how mine is set up . But when I feel my uturus , it feels sort of hard , but I don't see any kind of weight gain and I haven't been sick , just very constipated the past month . What I'm asking is should i be concerned and take a test ? I always have one just in case I have a scare like this because I'm aware the pill isn't 100% effective . Usually we don't take risks like this , but he was going away for a while and we kinda said fuck it then he got home from being away for around 2 weeks and we said fuck it again because we missed each other so much we didn't care . I take my pill religiously and always on time , once in a while a few minutes late but never hours from my regular time .