What Can Cause Delay In Periods?

Dear Chetna, Im 28yrs old married women, i weight around 72 kg. I have a normal periods which last upto 4- 5 days. I had an abortion when I 24yrs & after 3 yrs i started having period which ends by 3rd day. Still my periods were normal but last year (2009 June ) i dint had my periods for 2 months, I did the pregnancy test thrice but the result was negative. then i consutled a doc, she gave me medicines to get periods & asked me to do FHS & LH test on the 2nd or 3rd day of periods. After going through my results she said my LH level was high ( 9.00) my FHS level is normal (5.8). She in order to bring the LH down she prescribed me to take contraceptive pills for 5 -6 months. i started taking the pills from August 09. After 5 months (december) i stopped the pills but i dint get period in january & got it in Feb 2010. Again i did the LH test & consulted her by that time by LH was 7.1, she asked me to continue till I wanna conceive. i dint take my pills after i got my periods in April as we were planning baby, but after 1 week of my periods i gagin started having a slight periods and now this month i dint get my periods. Kindly suggest me what to do, i really wanna having baby.