My Transmission on my 05 Hyundai Tuscon keeps bucking & engine failure

What is your question?

ok, so this has happened for a about 2 days, and ive done all the searching I could, but, my transmission (at times, not so much, but its happening more frequent) will buck around and struggle to shift or catch a shift. Today 09/14/18, it wouldn't even accelerate and did the bucking bull act and completely shut off the engine and all. I checked the A/T oil, and all of the points are covered in oil, it's not over filled either, because the last time that fluid was touched was god knows when. Usually it was just that the gears wouldnt catch where they needed to be, but after today, that's different. So now, I don't know if I'm gonna need a new transmission, or a fluid flush, or if its the speed sensor. Please, anything that helps me will be highly appreciated.

How long has your 2005 Hyundai Tucson had this problem?

About a week or so