2006 BMW X3 3.0i Violent Shaking

HI Everyone,

I bought a cheap daily not knowing how expensive it would run me in the long run lol This has been by far my worst financial decision but alas here we are:

I started noticing a rather heavy vibration on the way to work today that its never done before, and it has been progressively getting worse. The shaking makes the car undrivable at above 50mph, it has a rough idle that jumps around and shakes the car. It drives smoothly for the most part except obviously above 50MPH.

-Vibration starts at about 30mph and is worst in the 2500-3000 rpm range
-Stops as soon as I take my foot off the gas - but still has a rough idle
-Is there in all types of gradients, but seems decidedly worse when going uphill
-Gets worse as I increase speed

The 4x4 light doesn't come on, and I don't notice any problems when shifting gears. I listened for the clicking sound the transfer box presumably makes after turning the vehicle off, but after several attempts, I have not heard it.

I would like to preface that is has an oil leak as well which I'm trying to take care of but my theory it is due to the fluids being low, trans fluid, diff fluids and also engine oil. When i bought the car i checked to see if it was leaking but i think they had cleaned the car so there were no signs of it.

Car has about 167k on it and i don't think it was taken care of its whole life as I've had to replace a lot of things.

Projects for this weekend from the things ive searched in the forums:
Check fluids: add as needed
Check driveshaft for play

any suggestions would be greatly appreciated as I am not trying to spend anymore than I need to. Thank you in advance.