Implantation or period

So my period is supposed to come in 3 days that's what eve is showing me. And last month the app was pretty accurate although I got my period a day early. But that's accurate enough and that's the first time it's been accurate since I got it because I had to take plan b pills twice Bc of an incident. Well today I started bleeding and it was light bleeding when I wiped it was pure red blood then I wiped again and it was still red but it wasn't much so I put a liner well couple hrs later the blood that has been on my liner turned brown Bc it dried. Well I wiped again and this time it's somewhat brown and red at the same time. Me and my bf are sexually active and we've had protected sex a couple times there was only 3 times where we messed around without one but he never came to the point of ejaculating. I told my bf about it and he said there's no way it's implantation bleeding Bc the fact that we check every condom we used to see if they are busted and if we just mess around he makes sure he doesn't pre cum. So idk if the brown blood could be an old blood or not. Or there's something wrong with me. Please let me know I'm pretty scared and worried.