I was in the same boat last month. My period was 2 weeks late but preg tests negative. I ended going to the doctor to do blood work. I wasn't pregnant. I got my af on 3/28.
Good luck
You could be pregnant, but it could just be that you are having an off cycle. When was the last time you tested? If you haven't tested in the last week I'd say take one more test and if it still comes back negative then call your doctor. There are many reasons for a delayed period, pregnancy being only one of them. Good luck to you!
Call your doc and go in for a blood test. You will know if you're pregnant and if not, you will be able to talk to your doctor about what is going on and causing the symptoms. (You should be to call and have the blood test ordered)