1990 Dodge Dakota Bad gas or something else?

After filling up with gas last night, my 1990 Dodge Dakota shakes something fierce and makes some god-swful sputtery noises that have never come out of my truck before. It doesn't seem to want to hit speeds over 50 mph, and when it does, the engine will rev itself randomly. Also, I stopped at a light last night and when I pressed back down on the gas for the green, it barely moved, choosing to not go faster than 5 mph, until I pulled it over. The steering seemed tight when I tried (no problems with that since then) and when I restarted it, it had no problems with the speed. But it still sounds like death in vehicle form and shakes so much my cd player skips. Is it bad gas or should I be looking for something else wrong?