Looking for some advice

Okay so my Fiancé and I have been TTC for about 5 months. This month AF was due Friday. It’s now Tuesday and I haven’t gotten my period nor have I had cramps. When I get my period it’s never this late as well. Always a day either or up to a day or two later. This would be the longest cycle I’ve ever had if i do end up getting my period. Well, the other thing is is that I took a pregnancy test a couple days ago and it said negative. I’m just looking for advice weather this has happened to you and you got a BFP later down the road, or if I should call my doctors.