Hook effect?

Ive been getting back and forth test results from positive to negative and so forth... If i am pregnant id be probably about 8 weeks. I tried something out last night i diluted my urine and took a test and i got a faint line.. But that line is more visible then the other lines i am getting... When i test with first morning urine it looks negative... When i use dilutef urine it looks faintly positive and ive tried different brands... Could this be the hook effect or what else could cause this?