pregnancy or just late period ?

hi ladies i hope you take some time and read this to help me , because i am just a little confused. well my cycles are 28 to 29 days and at the longest i started on cycle day 35 . i am now on cycle day 36 so i passed my limit. i took a pregnancy test beofre i missed af it was negative , then i took one on cycle day 31 also negative . i'm thinking i am not pregnant. the day my period was supposed to start i wiped and had very light pink blood so i put a pad on then nothing showed up. i've been having cramps like af , headaches, very hungry , normal pms symptoms except my breast don't hurt ? but they have gotten bigger an my nipples burn and i can feel them aching . are these symptoms just of a really late period ? or should i buy another test ?