AF still not here...

I hate my body right now. I tested again this am and it was Negative..I usually get AF right on time on day 27 or 28..this is day 28 but it's still not here and the day is almost over. I'm glad that it didn't come yesterday because on day 3 when I'm supposed to start meds it would have been friday and I had the bachelorette party that night. I was sooooo worried that i'd have to do my first shot in a bar!! Now i'm worried that my whole cycle of meds will be set back if I get my period tomorrow but they can't take me in to do the baseline and day 3 will be sunday..if i don't have my baseline I can't start my meds...this blows. I just hope AF comes tonight so I can call them in the am and get an appt. I mean don't get me wrong..i'd be happy if it didn't come at all but i tested negative so therefore i feel that I am def not pg...