Transmission issues
 

My 2008 Nissan rogue is not having a proper shift.., it moves sluggishly while on drive and after a while, while continously applying the gas pedal it moves on a normal speed until the brake is applied to stop the process begins all over again.., also to this effect if the gear selector is on park it refuses to reeve but while the gas pedal is been applied for a while the engine reeves.., I have tried to fix it seem difficult.., please what can I do to rectify this issue.