3 months of period but not pregnant

Me and my other half have been ttc for 9 months now, no luck we have lots of sex usually every other night throughout the whole month! We are both getting alittle worried as we imagined it not taking this long   anyway the last three cycles my period has been about a week-two weeks late but I am still getting period cramps when I should be getting them but I am cramping for like a week to two weeks til my period starts. Is this something to be worried about?  This will be the third month of a late period that's almost two weeks late x