Late period & negative results?

I’m 13 days late for my period and I don’t know what to do. Im not on any birth control, I’m not stressed, my period isn’t irregular ( I had it last month on the 12th ) and I’ve had late days but only less than 4days. I AM trying for a baby, (Me & My Husband) so there really isn’t any tension on this. I’ve been feeling light cramps in my abdomen area but not severe. I’ve been nauseous, and I’ve been having some trouble sleeping. My lower back and my whole body feels uncomfortable when I sleep. I just need some help