Maybe Pregnant, Maybe Stressed?

Ta
My husband and I use condoms as our only form of birth control. We haven't had any legitimate "scares" however, we had unprotected sex 2 days before my period (so I shouldn't be ovulating AT ALL).  Now my period is 6/7 days late. I took a pregnancy test at 4 day late and it was plain as day negative. I have yet to start my period. I have signs of a period but it just hasn't come which I know can be a sign of pregnancy. Also I noticed when I was 2 days late I had discharge similar to when I ovulate. Now I have a discharge that resembles a "pregnancy" discharge (milky not cottage cheese but slight different odor). Last I'm been constipated too. 
Background info: I have never been late by more than 3 days ever. I have a perfect cycle. If my stress affects my cycle it makes me have a period early, never late. Also I have recently changed jobs which is stressful but my anixiety has been intense lately but I'm not stressed about my new job. I was a really smooth transition... I'm wondering if that could be a mood swing from pregnancy. I have had trouble falling asleep and tiredness 24/7. I have felt nauseous but that has always been an issue I have dealt with spontaniously. 
We are planning on having a baby within a year so this would this "scare" doesn't have me scared because of pregnancy but that something is wrong with my body.