Engine feels bogged down
 

Two days ago, I cleaned my air filter (K & N with a cleaning kit) and added some oil (possibly too much). Yesterday, I took the car out and the engine feels like it's being bogged down in the whole rpm range. I'm also feeling some odd vibration in the clutch pedal and the gear shifter.

There is also a little whistle noise at highway speeds, sounds almost like a pressure cooker. I've been hearing this noise for just over 2 weeks now, but it doesn't seem to be effecting anything.

I'm very afraid that something internal may be damaged if I drive it any right now. I'd rather not drive it unless I'm going straight to the dealer for a repair if needed.

EDIT: Sorry, here is some info on my car:

The car is a 2004 model at 98,000 miles. The engine was replaced under warranty at around 80,000 miles. Spark plugs and coils were put on at the engine replacement. I do have regular oil changes every 3,000 miles and I usually keep the oil topped off after 2 fillups.