transmission problems 2007 toyota camry

Hi, I have a 2007 Toyota Camry XLE automatic transmission. When the car switches from 2nd to 3rd gear, the transition is rough and the engine revs. It goes away after a few minutes of driving. I bought the car brand new and about a month into it, I started noticing this problem. This has gotten worse and worse over the years, but the car is still driveable. Your feedback is appreciated.

Not an easy thing to advise on over the net, it should be scanned with a trans specialty scanner that can look at slippage errors and other transmission functions.