Question =]

Ok..is it possible to get a false positive hpt if you have pcos? I'm do very confused. I had a faint positive 9dpo everyone on here saw it and I saw it. Nothing but negatives after that, no bleeding or anything til I started my period. My last two periods have been very unusual for me. Having pcos (or so I've been told) I have regular 26-28 day cycles and they last a week. My last two have been 2 days with a day or two of spotting and closer together they keep starting a day early. I just don't understand how I had a positive hpt then nothing after.