Possibly pregnant?

My period is never late. Maybe a day early, but always on time. I'm 3 days late with some spotting. My boobs feel bigger, but they don't hurt. I've been so hungry lately. My sex drive has toned down a bit. The only pain is a little bit when I start to get nauseous which is usually at night or after eating. I have taken 2 clear blue digital tests (one on the day of my missed period, the other 2 days after) and both said negative. I also read that clear blue detects higher amounts of the pregnancy hormone so it could be off. I can't sleep and it takes me forever to get comfortable. Plus I've been having frequent headaches and my vision is worse than usual.