To change your user name you'd just need to message Anna or one of the other administrators. Anna commented above somewhere on this thread so if you click on her name on that post it should give you the option to message her. I adjusted my name a while back as well.
Most of us come here with our lives made unmanageable through alcohol. But we gradually clear away the wreckage as we get sober and work on our recovery.
Stay safe, and keep reading and posting here. Re urine colour - if you're at all worried get checked out. Maybe they'll send you away and say you're okay. Which would be good. And maybe they won't, and then you'll be glad you went along. Best to err on the side of caution I'd have thought.