In the last few days

in the last few days my bmw saloon 320i on an M reg has started kinda jumping on the back end...

I hit a manhole and the back end moves off it plus going round corners has become a challenge, it seams that the back end it literaly moving by itself.

it's started since i carried alot of weight in the car, not excess weight but it was heavy.

it's scaring the **** out of my, ive jacked it up and had a look and there dosent seam to be anything wrong and the tyres etc are good aswell.


Also ive got a massive problem with my heaters, there's a gurgling noise when i switch the car off, it seams to be coming from the heater matrix i believe. the heaters work on 1 and 2 but there's nearly no power but 3 and 4 seam to have the power of 1 and 2 in a normal bmw. the vents coming to the windscreen dont work at all, niver do the floor vents but the face vents work ok. when you turn on the air con there's no freezing cold air and when you switch it on it sounds light a fighter jet has just fired up, it's so loud.

Id be very gratefull for any help you can give me.