Increased anxiety is very common when starting (or re-starting) antidepressants. If that's all it is it shouldn't last more than a few days to a week or so.
*Very common (10% or more): Insomnia (up to 33%), anxiety (up to 15%), nervousness (up to 14%)*
*Very common (10% or more): Anorexia (up to 17%)
Common (1% to 10%): Decreased appetite, weight loss*