TTC missed period

My husband and I have been TTC for 18 months. I have a 29 day cycle and works like clockwork. Never late or early period. I was due to start my period seven days ago, so I'm a week late. I had some very faint spotting(?) while wiping about a week before my period was due. I took a pregnancy test today and it said negative? Could I still be pregnant? Has anyone gotten a negative after being late and get a positive later??? I'm trying not to get my hopes up.