clutch?

Sounds like two different issues.

The first sounds a bit like clutch "chatter" and occurs when the clutch is taking up (i.e. you're still releasing the pedal) from a stop. It can happen if the clutch has been overheated and the disc faces are glazed, if the flywheel or pressure plate has heat checks, if the lining gets contaminated with oil etc. Sometimes chatter can occur on aftermarket "racing clutches", especially puck type discs, discs without sprung hubs or without marcel springs etc. Depending on the cause, sometimes the condition goes away on its own if the clutch is not abused for a while (e.g. faces are glazed) or if its a racing clutch, you'll have to get used to it.

The second sounds like typical "lugging" behavior. You say you're in top gear "going slower than i should"; I suggest selecting a lower gear to alleviate driveability issues seen when lugging.