Just be sure to change your password and if you use it for anything else (which you shouldn't ) then change those too. You'll be fine.

As for your dream related questions; Yes, you do walk around in a dream if you want to. Some prefer flying, others teleporting, it's a matter of preference. If you choose to walk it is just like waking life though, you just walk. You have to "think" about it the same as you would in waking life which, unless you're a toddler, isn't very hard.