Confused.. stressed!!

Hi, my name is Tara. I'm 34 ttc baby#6.. I know, I already have 5 healthy children but I want one more before I feel I'm done with this part of my life. Anyway, my period is 7 days late which is completely abnormal for me. It has always been like clockwork, every 30 days.. I took a pregnancy test when I was 3 days late, may have been too early, I don't know. My husband and I only had sex one day in March, due to some medical problems he has been having. So.. the day was not a high fertility day for me and I don't believe I was ovulating either. I'm getting really frustrated and stressed about this. I did recently start a new job, where I work 9 to 10 hours a day and extremely active, I'm lucky if I get to sit down for a couple minutes.. so, my question is, could this be the reason my period is late? Stress and a big change in work, or am I just worrying for nothing? I am going to get a pregnancy test today and maybe wait until the morning, if I can, Haha! Any positive info or opinions or thoughts would be greatly appreciated!