It’s possible. For me, the symptoms like sore breasts, fatigue, and nausea all came after I took a test. At that time, I was about three weeks along and the symptoms came a couple of weeks after that. By the time I’d taken the test of course I’d already missed my period. You might want to hold off until you do miss your period before testing just for better accuracy. Are you going on birth control once (if) you do have a period? If so, that would work out just right because you could begin the new pack the following week after your period. It will get your periods regulated after that. The headaches and heartburn are the sort of symptoms that could be anything, so I wouldn’t put much stock in those as signs of pregnancy.