started to rev louder than usual, it also seems to be losing power

Hello,

We will need a bit more information to be able to guide you along on this. Many things can be causing a loss of power, a simple tune up may be all it needs. A clogging air and fuel filter would cause a loss of power as well as if the ignition system isn't tip top. If the check engine light is on getting it scanned and letting us know what codes it has will help. What type of smell are you getting? If its like rotten eggs then that would be your oxygen sensor bad. It too would make it run bad.
I've attached an article on doing a tune up for you to get done and one on a low power issue.
Review these and let us know.
Tom

https://www.2carpros.com/articles/engine-has-low-power-output

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine