There are people that have been fired because of their on-line "identity", so to speak. I honestly wouldn't worry about it. You're not doing anything wrong or illegal, and if they wanted to fire you, they'd have to have a real reason to do so. Just make sure you're not using the company computers for anything other than work. If they let you go because of an illness, you would have just cause to sue them. They're not allowed to discriminate against you, or anyone else.