Hi, ive got an early 90

Over the past couple of days, whenever i get over about 15mph
i can hear a sqeeking sound coming from somwhere underneath.

although when the clutch is down it goes away.

Also when i hit about 30 -40 mph the whole thing starts to shake quite badly (worse than normal) the whole steering wheel shakes in your hands, but then if you let off the throttle, the shaking stops.

ive looked everywhere underneath and cant see anything loose or not as it should be,

god knows! any help is greatly appreciated

is it a seized or knackered uj in one of the prop shafts?

The shake could be the wobble of death, check swivel joints, front bearings, shocks, steering damper, track rod ends etc.