Q: My Mercedes-Benz Clk320 is vibrating and shaking and and won't accelerate even when the pedal is to the floor what do I do?

Well everything was going fine until I was trying to accelerate on the freeway and as I was accelerating I heard and felt the car move and it would not continue to accelerate, instead the needle on the speedometer started to slowly decline and I was decreasing in speed I would let go of the gas and press it over and over again but nothing would happen and so finally I pressed the gas hard until it was on the floor and the car just sounds like it accelerates but its just stalling or something and I continued to decline in speed, I pulled over and turned my car off and then back on, it was fine for about a minute or two and then repeats what just happened again and again and for that I'm asking your help and see if you guys can help me fix it myself or something.

My car has 117000 miles.
My car has an automatic transmission.