I've been on Paxil (paroxetine) for almost a year, why am I still anxious?

Anxious. Medication alone is not enough. Need psychotherapy to learn coping and behavior control. Also explore if your anxiety is situational & work on modifying such.
Add adjuncts. I agree with dr. Ali. There are many possible adjuncts you can use. Yoga, meditation and acpuncture are excellent options. Try deep breathing exercises or progressive muscle relaxation. Cognitive behavioral therapy is often beneficial for treatment of anxiety. It is important to let your prescribing provider know how effective your medication is as well as any side effects.