Help !!! Pregnant or not ??

So last month i was late with my menstrual. My breast were sore for about the entire month, i been getting some strange headache , hard time going to the bathroom. Just recently started feeling nauseous, and this nasty feeling in my stomach. I got my menstrual two days before the month was over.. so i felt relieved.. but im still feeling terribly nauseous so i decided to do a pregnancy test and it came out negative at first then when i was ready to throw it out another very fainted line appeared then disappeared.... what does it mean??