Not sure if I should be concerned??

So, just to give all the facts:
Last month, 1 day after my period had ended, I had u protected sex one night, then protected sex a few times after. 
My period is never very regular so when I'm a few days late I never question it. This month, I was about 5 days late (which is totally normal for me) then when I got it, it was waaay heavier than usual. Like, usually I can got 8 hours with one tampon but i bless through three tampons after a max of 6 hours each one day. 
I'm just not sure if there's anything I should be concerned about?? 
Also, I've been very stressed lately with all of my classes and homework, so could this be a cause? 
Thank you lovely ladies in advance 😘