I've actually had a similar problem now that I think of it.
Chat.StackExchange Reputation Bug?
The mods were able to force refresh my account but I was able to get around it by switching my chat profile's parent account to a different StackExchange site and then back to GameDev.
Your chat account is here: http://chat.stackexchange.com/users/75273/theprogramm3r
There should be a [change] link right by the parent account field. See if that works for you.

** Assuming it was appropriate I would add the below details to the question if I could edit **
JohnMcdonald disappeared around 9:18PM chat time
JohnMcdonald reappared around 10:27PM chat time reporting similar problem as reported in the question
John reported the following details regarding what he noticed around the incident:
Available:
Rep on Gamedev; Check votes on Gamedev (needs some rep); Account on GD.SE, SO, and others; Chat on SO only
Not Available
Chat on anywhere except StackOverflow (sites affected included GD.SE and Arquade)
"Logging out and in didn't work, clearing cookies didn't work, using a different browser didn't work. I just had to wait 1 hour then everything was back to normal ... I was in chat at the time. I sent one message, and within 5 seconds, I tried to attach an image and it failed because I didn't have rep."
John reported that his network displayed exactly like the following image and was still displaying the symptom, though chat was now working. I have confirmed that TheProgramm3r's network profile is having the same issue as of right now.

John was unable to confirm whether or not his chat profile showed zero reputation