No, you weren't hallucinating -- the President's personal Twitter account was unplugged earlier this evening. It disappeared, and then reappeared without warning or reason, however now Twitter is offering an explanation. The account was "inadvertently deactivated due to human error by a Twitter employee" for about 11 minutes before it was restored, so those hoping the company would turn it off for good are still left waiting.
Update: Or... Maybe not. Now Twitter is saying that after an investigation, it appears this was done by a customer support employee on their last day. The tweet did not note if it was already the person's last day before or after they turned off the president's account.