I need help!anybody?

Bre • 24...married.
Hi im bre im 24yrz old ... Me and my husband been TTC for 2yrs already recently in October i had my period for bout 4 days and ever since that i havent gotten my period. Its november .. I been getting cramps like im getting my stuff bt nothing. Can someone plz explain whats the matter.... I have tooken 3pregnancy test and they came out negative ! Can someone talk to me? And explain?