When i try to turn on my air condition in my truck my rpms drop way down and shut my truck off, help me please?

i left my lights on the other day and ran my battery dead, ever since then i cant run my ac, if i turn it on while driving it looses alot of power and becomes sluggish, and then when i come to a stop my rpms drop all the way down and it shuts off.. what is the deal?????