I took mr vaccine but before passing 3 month if I conceive what will be the effect?

Unlikely to be a pbm. Many physicians prefer to avoid this vaccine prior to, or during the first 3 months of pregnancy out of concern there could be problems.However, of cases where this has happened, there have been no significant issues reported.
Should have antibody. If you are going to form antibodies as a response to this vaccine you will likely have formed enough to prevent overt infection during your pregnancy. Good luck.