If things get really bad you are going to need to know how to have the advantage in any situation.
It is easy to pick up a bottle in a bar fight to use as a weapon, but what if you have to eliminate enemy targets from further away? What if by eliminating one or two from a distance will only leave one or two to contend with closer up?
One great weapon that has been used for thousands of years is a slingshot. Ideally made with surgical tubing, but can be made with many items. Easy to make and easy to use are just two advantages.
A slingshot is virtually silent and unless you are floating in the middle of the ocean, it is hard to run out of ammo. Practicing now will give you an advantage in the case you have to use your slingshot for hunting or for escape.