Volunteering sounds like a good solution for the short term. You can find out whether you're allergic and how badly, and I'm sure there are dogs who need attention somewhere nearby.

On practice pets: A lizard can actually be more difficult to cope with than a dog, because it doesn't ask for things or give affection rewards. Big, interactive pets that pester you are easier that way. (Maybe you don't have nightmares about forgetting pets, but I do, and it's because I know how easily I forget to water my plants.)