Hey you,
I went through much anxiety my first six months probably. In my case, because I was working a program, I believe it was caused from shedding the "sick" me and the "new" me was slowly gaining control. It was surreal.
Program or no program, sobriety awakens our senses. Our self awareness is heightened once sober. We start to see things about ourselves and choices we made in a new and uneasy light. As we grow in sobriety and see new positive things about ourselves and see that we can make positive choices, the uneasy mindest diminishes.
At least that was what it was like for me. At three months anxiety is still very common. hang in there and just keep doing the next right thing, then the next, then the next...