Strange

Wondering if anyone has had the same happen. My periods are always regular, normally a 28 day cycle. For the first time ever time i am late on my period. I was due on sunday and its now Wednesday and i have started bleeding SO light. Hardly anything at all (its normally quite heavy) ive done a pregnancy test and its negative. No cramps or anything either. Has anyone gone on to actually be pregnant? Still hoping maybe i am and the test just hasnt picked it up at all.