Hi J.,
Chances are it's way too early to tell. I know how hard it is to wait but my sister had this happen to her as well, and she was using the expensive EPT tests the one's that are supposed to be 99% effective. Only she took the test 4 days early like they say in the commercials and it told her it was positive. She got all excited as they've been trying for two years now, only to find out 4 or 5 days later she started her period. My suggestion to you is to try and hang on and wait until your period is late. Then go get a blood test. Most OBGYN's will tell you that at home pregnancy tests are inacurate and can show you a false positive more often than not. I know it's tough, but I'd wait it out and then try it again when you're late, and take more than one test to be sure, if you're using an at home test.
L.