Hello all.
Before i begin i'd like to say that im practically a novice to the more advanced functions of a car. In other words my knowledge is limitited to tasks such as...hmm..refilling the motor oil and wondering if that sticky stuff i just got on my fingers is poisonous.
I'm hoping i can get some aid in identifying what the following symptoms mean:

In first gear, after rolling a car lenght or so, the car suddenly wants to slow down. I have to push the clutch to the bottom to keep rolling (and prevent the engine from shutting down) - or push the gas close to the bottom (which results in the car gaining speed after 2-3 seconds of making a quite loud noise). Definately feels like im forcing it.

This only happens on low speeds in first gear.
The noise that is heard i can only describe as metal scraping, but not that screeching sound, more like that dark sound you hear in submarine movies when the hull is breaking apart.
On higher gears and speeds, the only evidence of the problem is a "shaking" or "trembling" of the break pedal, noticable when pressing the pedal down lightly.
Some days, theres no trace of this weird behaviour, the car functions fine. But 70% - 80% of the time its there.

At this point i have no idea wherein the problem lies. Is it the breaks? the transmission? the fuel injection? If it was the breaks, why would it settle down when i press the clutch. If its the transmission why is the breakpedal trembling etc etc..

I've read through countless sites in order to try and figure out what it might be but theres just too many possibilities.
And unfortunately at the moment my economy doesnt allow for me to take it to the shop, i basically want to know what might be causing this so i can plan accordingly.

Any help would be greatly appreciated.
Cheers.