Your symptoms sound exactly like your catalytic converter is clogged. Have a pressure test done on your catalytic converter by a muffler shop. They go bad and the ceramic elements can break up which will clog it enough that the engine can't pump its exaust gasses through which significantly reduces higher rpm power.
Go to a small non-chain muffler shop to have it tested as they will do that kind of a test without trying to rip you off like Midas likely would. Your symptoms certainly point to that clogged cat possibility.