HELP PLS ANSWER

Hey guys!!! Just a girl here that needs a bit of help. A little background before: I am sexually active. i ALWAYS use condoms and check the condom after we are done. But I have a concerning situation. My period ended two weeks ago and i had sex the day after it ended but just a few days ago I have been getting this thin brown discharge , but A LOT of it. It’s never happened before and i’ve had a bit of cramping. i’m not really sure what it is and i’m really worried about it. does anyone know what it could be?

I’ve looked up to see what implantation bleeding looks and feels like but it’s supposed to happen around my period, but that wouldn’t be possible since I just got off of mine. i’m a bit concerned that’s all and I would appreciate all the help/ answers:)))

THANK YOU!