Late period

Heyyyyy Guys so there's this problem that I am experiencing and I don't know what to do about it . My last period was dated back on sep17.2015 I did not receive a period in October and November is here and still no period. I took about 3 test all were BFN and now I'm about 55 days late. Any possibility of what could possibly be going on ? Any advice is appreciated I am going cuCOO! 😔 thanks so much