As stated above, the only time your character remains dead is if they:
1.) Died by suicide (this is generally to prevent players from killing themselves to avoid RP they don't want to participate in)
2.) Are voted to stay dead by GMs/Admins (this rarely happens, and usually only for important/controversial characters)
You're more than welcome to continue playing that character. One thing, though: Your character loses a bit of memory pertaining to the encounter. They won't remember who killed them. This is to prevent metagaming.