mazda mpv04 tranny problem

something happened to my transmission( mazda mpv-04) on my way to thunderbay on 04/25/08, it was going good then it strted jerking came to a stop when i tried to put it in drive the overdrive light was blinking along with the engine light and it would only go 20-30 km per hour while i had to put the other number thing at 4 just to go this fast please help dont really know alot bout vehicles