Check your u-joints first. If they are worn out and have a lot of slack in them they will make the "jumping you described. When you say you put it in reverse and it "jumped" that could definitely be u-joint. Its not making a pooping noise by any chance, when you go forward or backwards?
Start with the u-joint and work your way down the drive line to the rear axle. Check to see if the pinion bearings are worn. Just grab the pinion, about where it meets the drive shaft, and pull and push it quickly. Nothing, and I mean nothing, should move when you do this. If it does I would take it to a shop and have it repaired ASAP.
Also check your rear wheel bearing. It is easy to do. Just use a jack and lift the rear wheel off the ground. Grab the tire at the top and bottom and move it back and forth. If you get any movement out of the tires then the rear axle bearing should be changed.
Checking these item will help in your problem solving. Always go with the simple stuff first before you take it to the shop.
