Not sure what group to post this in... help?

So, I took a Plan B, and I’m guessing it kickstarted my period. The only thing is, I had my period a week ago..

It’s bright red blood, no clots in it, and it’s literally a heavy, constant flow. The blood isn’t thick, it’s like a heavy nose bleed. It’s to the point that when I change pads, there’s already a decent amount of blood on the new one a few minutes after. I have to change my tampon a lot more frequent than my normal period due to it “overflowing”.

I’m just not sure if this is normal and it’s kinda scaring me. It’s been happening for two days so far. I’ve taken a Plan B twice in the past and this has never happened.