What Causes Delay In Menstruation Other Than Pregnancy?

hi doctor,

m 24 old female,

1) i have 2 months 18 days of missed periods

2) urine test to detect pregnancy says negative

3) harmone test done - harmone level in range (absolutely no problem)

4) blood test to detect pregnancy says negative

doctor says no problem n asking just to wait unless n untill i get my Mcycle normally else can take the tablets to get my menstration...

*** I want my periods to happen normally*** (without any tablets to let it happen)

5) Doctor is not suggesting for "Pelvic scan"/ultra sound ,,,till the urine/blood test shows positive...

*** kindly advice,,,should i wait or any action to b taken ???

6) last detailed abdomen scan done in feb'2010 last week ...states,,, that every thing is fine from my end and doctor knows abt it..

looking forward to hear from you..

thanks in advance,

lousi