When my Saturn shifts into gear at about 25 miles per hour it jerks hard on 2008 Saturn Outlook

when I stop and then begin driving it's slow in going and then it will jerk at about 25 mph. what is wrong with it? could it be the clutch wave plate?

thank you

Asked by for the 2008 Saturn Outlook
Sounds like a transmission problem. I am not very familiar with Saturn. When was the last time the transmission was serviced? Also some shift issues on cars are resolved with a transmission control computer re-flash.
I had the transmission fluid flushed/replaced 2 mths ago, last week it started making a squeeling sound when I would accelerate. I brought it in and it was a quart low on transmission fluid, thought that was it, then the next day that's when it started jerking. What is the transmission control computer re-flash?