My brakes bind overnight, my drive is on a hill and letting off the handbrake in the morning (read: afternoon, unemployment is fun) doesn't release the car from standing. As I pull away it feels like all 4 corners go *thunk* as my brakes unbind. All wheels turns freely when jacked up with the front pads making contact but barely slowing the wheel at all.

Should I worry?

Its unusual that its doing it overnight. Normally takes a week or 2. Have you an unusual amount of water going past the car/splashing, or do you drive through a puddle on the way in.

Not normally no. It's been a dry night tonight, maybe I'll check it tomorrow.

The discs start to rust after like 2 days sometimes. I think they're very cheap ones.

Take off the rear drums and make sure they're not too rusty inside. If they are bad, then scrape off any loose flakes, and then put everything back together. Then carefully apply the handbrake till the shoes just very slightly start to bind and then drive the car for about a quarter of a mile. Then release, let the drums cool down and then reinspect.

paraffin scrub and rinse then high-temp grease all moving parts in the drums.
check the rear bearings for roughness and play too. if that fails you might have very chin chin cheapo brake shoes.
make sure the release springs on the shoes are strong.