I'm late and have endometreiosis.

So I have mild endometreosis and I've been useing glow since October of 2013 and it's always been 28 days apart- 32 at most well I'm 35 days as of today since my last period ended and 9 days since I was suposed to start I have a doctors appointment this Friday but is it possiable for something to be blocked so I can't have a period idk I just wanted some thought and advice on this