Implantation or Period?

Hello moms or moms to be!

I have a common question. So again, I am new to all of this. I am 6 days late of not having my period. I am 1 week and 3 days since last having sex. This morning something new has happened. I noticed dark brown blood (not a lot) while using the bathroom. It was quite odd. So after a couple of hours, I checked down there again and the brown blood is very faint and light like it’s going away.

I am feeling very nauseous still. I am scared that I’d eat anything I will vomit and I have a full feeling, lower back pains, little cramps, and my head is pounding. I also have come and go sharp pains. I will keep monitoring this. I have googled everything but I’m still trying to understand what exactly is going on with me 😂 Any ideas ladies?