Just to inform, today i have found my perfect forehand.
My problem was not the unit turn, i was doing that okay but after i take my swing, i was not completing the hip and torso rotation and mostly arming the ball. Today i did everything right. Pivoting, unit turn, hip rotation, and as a result of that, i could feel the laggy movement of the arm and racquet due to the momentum of body turn. Whenever i had a complete body rotation, the racquet came behind and smashed the ball, totally effortless power. Also i should say that i had turned to a double bend arm forehand instead of straight arm and realized the straight arm was just not for me. It was one of the factors that destroys my rythym.
Want to say thank you guys, appreciate your helps.