Am I going crazy? :\?

I panic about the little things like, I can never sleep or relax with doors open (in my bedroom, living room, kitchen) and when they are open I keep feeling as if someone or something is watching me. I am hardly ever comfortable in my own home anymore. And when I'm out alone, when it's dark or light, I always feel as if someone is there following me. I've been getting a lot of headaches recently, and my doctor says it's tension headaches... I'm confused. Please help.