What Causes Delayed Period After Miscarriage?

Hi, This is Archana from india, i am 26 F, got married last year. i got conceived last year November (30 day confirmation). and when i was about to complete my 12th week on january 19th 2010 ( 3 days for 13 th week beginning), i got sudden miscarriage,The reason for miscarriage was unpredictable. we guessed that was due to drop down of hormone and had severe stress at my home during that period. When i consulted the doctor, she checked me thoroughly and every thing is normal, no particles inside the uterus. she suggested me to avoid pregnancy for three month from janaury. after three months, from may, we have been trying for the baby, it is ending up with my period. I am started talking folic acid tab and vitamin tablet as doctor prescribed.
Please give me some suggestion.