Are these symptoms all in my head? Was it just to early to take a pregnancy test?

Hello, I am having some odd symptoms such as sore breasts, slight period like cramps, headaches, and fatigue. I think these may be early pregnancy symptoms but I am not sure. I have been taking the birth control sprintex for two years and never had these symptoms form it. PMS usually dose not effect me in-till 3 days before my period and its a week away right now. I am worried I could be pregnant because I was nine hours late on a pill two weeks ago. I really want to know whats going on and why I am having these symptoms.... I took a test but it said negative but I was reading the back of it and it said that its only 50% accurate 5 days before the missed period but mine is 7 days away so I am not sure. I really want to know because I am afraid that if I am im hurting the baby by taking my birth control pills... I am really hoping its just all in my head but I don't know...