Fertile week please help!!!!!

I was due on on Tuesday but it never come so I tested and it was negative by Thursday I still hadn't come on so I tested again and it was still negative. It's now Saturday and I've still not come on but since my 2 tests were both negative I don't think I'm pregnant :-( does anyone know when my next most fertile week would be as it usually is exactly a week after I come on but now I don't know when it would be. Please help!!!!