tmi but right now im feeling constipated and sharp pain in my left boob just feeling tired and sick…

tmi but right now im feeling constipated and sharp pain in my left boob just feeling tired and sick to my stomach. today makes it day 1 of me missing my period and i already took a pregnacy test but i guess its to early brcause it said negative. so i wonder what it could be and i also been spotting. it will be my third pregnancy but i do know every pregnancy is different any suggestions. im trying to be patient and see what it could be. im hoping to be pregnant with my third baby and my husband's first