Clutch/transmission issues

[billz015]

It's a 1998 Nissan Sentra GXE, 1.6 liter.

I had the transmission replaced June '09, I dropped a nut in the engine bay forgot about it and it punched a hole in the transmission on the passenger side.

Now ever since the transmission was replaced the clutch hadn't felt right. Too me it felt like it'd be worn down or something by them doing that, before the transmission replacement the clutch had some tension to it and that felt right to me. Ever since it's been too easy to press in and and catches higher.

Last week on my way to work, it decided to not go into gear anymore. By that I mean popping it out of gear and the car seemed to shudder and then the gears just got hard like I wasn't holding the clutch even though it was slammed to the floor. I rev the engine and it goes into gear, the problem has persisted but I'm poor and revving it gets it into gear with no grinding so I drive it.

As recently as today if the clutch is fully engaged the car doesn't act like it is. First or reverse it just urges forward like the clutch isn't even there. My foot isn't on the gas, but the car is rolling forward. Same thing with second, and from third up it just stalls out. I only tested the higher gears because I'd heard if it stalls the clutch isn't bad how true that is, I don't know.

Obviously you guys can't tell me exactly what's wrong because the car isn't in front of you, but it's become obvious to me something needs to replaced or adjusted. Any ideas what it could be?