IT will not be covered under warranty unless something besides your driving had to do with it...which is unlikely. I believe the clutch master cyclinder is also the brake master cyclinder. So check that for fluid. If you are low, then you have a leak. It does not sound like your clutch is going out if it just vibrates though. Usually a clutch going out will mean it takes a little while for it to grab...meaning the rpms go up but the mph don't. So test it by putting it in third going like 25. Just cruise at 25 or 30 for a sec and push the gas to the floor. If the rpms go up more than supposed to, then your clutch is going out.
I do not know what a vibration means, but if it is not normal, then take it in. Good luck
Dan