Go back to your doctor with exactly the same request (doctors hate that). Print out the NHS guidelines on the treatment of anxiety (which includes pregabalin) and show them to your doctor.

http://www.nhs.uk/Conditions/Anxiety...Treatment.aspx

You could also point to all the side effects of SSRIs etc. Every drug has a list of side effects - that was a petty power play on the part of your doctor.

If your doctor still says no, say you want a second opinion, and ask for a referral.

Eventually, someone will relent - pregabalin has been an NHS approved medication for anxiety since 2006, but some doctors are still unaware of this (as your GP seemed to be), and just want to keep on prescribing the old familiar drugs.