Period 1 1/2 days help!?

So I got my period early in the morning 3 days ago and by half way trough my 1st day I lightened up a lot! Day 2 is normally my worst day and there was no blood on day 2 . I kept a tampon in for day 3 in case my period was playing tricks (you girls know what I mean) and kept changing it every 3-4 hours and no blood?

Here’s the catch ....

I had sex 2 days before my period started as I am 17 ttc ... so I’m a little concerned about what’s going on ? Any tips or help?

- I am gonna take a test in about 1 week and see if that’s the problem, but I am worried as my period has never been less then 3 days ! Thanks in advance guys! 💞