Pregnancy test!

I took a digital pregnancy test on monday it said yes, I have taken Line test everyday after that and nothing, well I cant see no line, I took another digital(different brand) on Wednesday and it said no, i tried taking another digital this morning and it disnt show nothing. So my question is, is it still possible to be pregnant even though the digital said yes and the line ones were negative?

Is it possible to have a false positive on a digital?

My period is due tommrow.