What Causes Delay In Periods After Discontinuing Thyronorm?

Hello Doctor, I have been trying to conceive since last 7 months,ie, since June 2013. I was married in November 2012 and was on birth control pills Femilon from December 2012 to June 2013. I had regular timely periods in July and August. But a delay of 5 days in Sept. Again a delay of a week in October where I had to actually postpone( used Meprate,3 tablets per day) the delay further for 3days,so a total delay of 10 days happened. Got my periods on 25th in that month. But again I missed my periods in November where I took two HPTs both resulting negative. Consulted a gynecologist and she asked for a thyroid test and prolactin test. My tsh was 6.3 and total T4(6.7), total T3(104.8) and Prolactin(16.43) were normal. She suggested Thyronorm 25mcg everyday and an extra pill every Saturday and Sunday. After the start of these tablets I got my period in December on 21st. But again missed in January. HPT was negative when I was a week late. I am now 22 days late and I stopped the Thyronorm since last 7 days as I was experiencing hair fall and sluggishness and feel tired quickly. Kindly please let me know what actually is wrong with me. What do I do. I am 25yrs old and I weigh 64kgs and my periods were always regular since past 12 years.
Thank you,
Hanitha