Though some televangelists may try to convince you otherwise, Jesus never promised happiness in this life. If so, early Christians martyrs would have certainly been disillusioned as lions gnawed off their limbs.
Even Jesus himself was not always the picture of happiness. John 11:35 does not say, “Jesus laughed” but rather “Jesus wept”. In Matthew 26:38, Jesus said that his soul was “overwhelmed with sorrow to the point of death”. The song Jesus sang on the cross was not “Zip-a-Dee-Doo-Dah” but rather Psalm 22 – “My God, my God, why have you forsaken me?” Clearly, it was not a particularly happy day for Him.
Christianity does not guarantee happiness in this life, but rather, Hope for the next. If you are seeking Nirvana, it honestly might be better to try Buddhism.