Transmission/ Clutch issues
 

I have an 04 6MT. When I change gears I sometimes feel vibrations in my clutch pedal while I'm letting it out. Also, I've recently taken my car to the track and I've noticed that when I upshift from 1to2 and 2to3 real fast it feels kind of rough and theres this weird sound when I've gotten into gear. It's hard to explain but it not a grinding or metalic sound its like a bong sound and I can feel the car kind of jumps like I ran over a small speed bump. It also does this sometimes when I go into 1 from Neutral. Hopefully you guys know what I'm talking about and can help me. Thanks in advanced