Could a blood test be wrong ?

I had a baby 10 months ago fast forward to now ... 2 days ago I had what at first I thought could be the start of my first period.. but it was only when I wiped and was a light brown color and only lasted a few hours and now nothing at all.. I have had cramping as well. This is what happened when I found out I was pregnant with my first so I decided to take a test that day and got a very very faint line ( pink dye test ) so today I went to get a blood test and it came back with hcg levels of 1. Is there any chance that this could be wrong ? It just doesn’t seem like that could’ve been my period it was so short and so light and then the faint positive..