need a little help

Hey everybody, I have a small problem I was hoping somebody could help me with.

I was driving my car down the highway today and experienced a problem. It is a 2006 chevy cobalt, manual transmission. I was in 5th gear when traffic briefly slowed to 45. I kept it in 5th gear and after a few seconds the clutch kind of pushed down itself a little and the engine revved to over 7000 rpms for 5-6 seconds before it returned to normal. For the rest of the drive it smelled like something was overheating or burning. On the drive home I started having more problems. When in 5th gear it feels like I lose power once I hit 55-60 mph and the car revs itself repeatedly up and down about 500-1000 rpms. it almost feels like a little hitch. When I come to a complete stop and then start accelertating the car shakes for a few seconds and feels like it wants to stall. It did stall once at the first stop I came to. I have no idea what the problem could be.

Also, no warning lights have come on. Thanks for any assistance anyone can provide.