If I remember correctly, there is something that can cause a false positive, although highly unlikely. I can't remember what it was that could cause it, but just try looking online and you will probably find it.
In my opinion, you sound pregnant to me

Some tests can detect the hcg sooner than others. When I was pregnant with my 2nd the cheapie Target brand test gave me a positive and the expensive First Response (2 in the box) both told me no. Just wait another week or so and make sure you test first thing in the morning where your hcg levels are the highest.