What Causes Delayed Period And Weight Gain After Taking M2 Tone Tablet?

hi doctor..my age is 23... 3 months back my periods got delayed.. I have checked with near by doctor. she took a scan and said as normal. she asked me to take m2 tone tablet and livogen(10 days) twice in a day for 3 months. I got periods for past two months. 3 rd month I have taken 7days tablets. I asked my doctor due to shortage of my tablets can I take those tablets for 7 days ; she said take it. but this month I didn t get periods. 10 days gone.. in September to November month 2013 I have gained nearly 8kgs. am sure am not pregnant... please help me what s my problem..is there any affect for my pregnancy in future?