I have taken a contraception medicine which contains only one hormone, I cannot use 2 hormonal one because I have migraine. I have taken that one only for 7 days then I decide to switch on condoms. But now I don't have my periods from last 6 months and putting on weight continuously. What is the best way to normalize my cycle?

This is something best discussed with your doctor. We don't know your medical history, and therefore can't give you the best advice.