Bigger breast and appetite keeps increasing

Well my breast keeps getting bigger my next period is supposed to be coming up soon but I have not had any signs of it yet and breast has been getting bigger since last month. As for as my appetite I just seem vet hungrier and hungrier every time I seem to eat it's like I never stop eating. I took a pregnancy test a dollar one.from the 99¢ store and it said negative but every pregnancy test is different right? && what if my cycle doesn't come alone this month, then what?