Last night I started what I thought was my period I had cramps but when I checked there was a very dark blood in my underwear, I've stayed up all night and it has completely stopped when I whipe there's a bit of dark blood. I had unprotected sex with my husband exactly 7days ago, could this more than likely be implantation bleeding? Please help!

How do you expect anyone to tell you if you are pregnant or not, after 7 days, if you are pregnant or not. You will have to wait till your next cycle and then do a test with first morning urine.