Or it could be a sign that your clutch is starting to go bad. Mine started a while back with just making noise when I let out the clutch which I thought was just the pedal. Now, once the vehicle has warmed up it will squeal constantly whilst the clutch is depressed, so it is progressing further and will have to be replaced in the future. I just try to drive like a responsible person in the meantime while Isave up a little coin for a clutch and flywheel combo. Keep an ear out because your symptoms are EXACTLY as mine were. Hope that helps bud!
1998 323i Convertible