Pregnant? Not pregnant? Too soon to know?

Andreia
Hi everyone... I've been trying to get pregnant, since I had a miscarriadge last November... Usually my cycle is 29-31 days, this month on the 28th I started spotting, pinkish first, and then brownish... 
My period hasn't come yet, I'm on day 36. Yesterday i thought it was coming as when I wipped myself it was red, and I saw a drop of blood in the toilet (sorry for being so graphic). 
Today nothing like that again, back to brownish. I did a pregnancy test when I woke up, and it was negative. 
I just don't know what to think, as last time I was pregnant the test was positive on the 1st day after I missed my period...