@Nich Just make sure you practice an Internal form of yoga or Chi-kung. The physical movements are there to help your brain go quiet. It is very simple but not necessarily easy. It requires persistent and regular practice.
Have you ever tried any Yoga or Chi-kung practice to battle anxiety? Regular practice has been linked to increased GABA levels in the brain:
http://www.ncbi.nlm.nih.gov/pubmed/17532734