Transmission problems??

I have a 1999 Automatic Grand Am GT and recently the shifting is taking about 3 seconds to shift into the next gear. Why is that? Also yesterday I was going about 50 mph and the needle for the rpms was at 4000 rmps and i dont think it should be there then i went faster and hit 80 mph and this time the needle was almost at 6000 rpms and i know for sure it shouldnt be there, and at 80 mph my car started to jerk violently and i couldnt go any faster than 80. Can someone tell me what is wrong with my car please. Thank you.

Seriously, something either wrong with your trans. or one of the controls. Hang around, someone who may know more specifically may chime in. Is your trans. fluid level okay?

The jerking was caused by the rev limiter in the ecm, its there to prevent engine damage from over reving. It sounds like either the shifter cable is out of adjustment, trans fluid is low or dirty, or a clutch pack in the transmission is bad (had this problem with a buick).

so if i get it fixed will i be able to go faster again?

I don't see why not unless there is a cop around you when you try it...