Alright, I'm the first to admit that I know almost nothing about cars. Except when something is wrong.

In the past few days or so (started on Thursday after driving back from Louisville), my transmission has been having trouble shifting gears. When it began, I could accelerate normally for a few miles before the car would seem to slow, then the RPM would jump uncharacteristically until settling back down (in this case, it would go from about 2 then shoot immediately to 3 with even the lightest of pedal taps). The car would also physically seem to lurch with each change. This happened even while in cruise control.

I let it sit overnight, hoping that it was just the awful KY heat, but when taking the car to work in the morning the trend continued. I plan to take it in to a mechanic to check the fluids etc, but was hoping to gain some insight from you experienced folks on what might actually be happening under the hood. My father did install a shift kit last year as part of an effort to extend the life of my current transmission, if that makes any difference.

I will try to answer any questions I can to better help you guys understand what's going on, sometimes I know I'm not the best at explaining things!
Thanks!