What did I do?

I turned my 6-speed truck around in my parents driveway and started drifting down the hill. I usually put it in second and coast down their gravel driveway. Today I did that but it was actually still in reverse and it did seem to be pulling some gravel but that's not unusual. When I stopped at the end of the driveway to pull out I noticed it was idling higher than usual. Once I hit the road I started shifting and I think it was when I hit 3rd that it started acting crazy. It felt like I pushed the clutch in a little then let it out real fast. I drive home short shifting without problem but it still seems to be acting crazy. When I pulled into my garage it was still idling higher than usual.

Any ideas?