my car is stuck in one gear how can i fix this on 2007 Mitsubishi Galant

i was cruising down the highway with my cruise control on and it just jerked so i pulled over and shut off my car. i checked it out an didnt find no leaks or anything broke. when i sarted it back up and put it in drive my "N" light started flashing and my take off was slow. i drove it to 50mph and notice that it wasnt shifting to 4th

"help me out, please!"

Asked by for the 2007 Mitsubishi Galant