Sorry, Simon. Can't pass the Prozac because it's a prescription drug. You'll have to phone your local surgery and (assuming you can sweet-talk the receptionist) see a GP of The Practice's choosing in a few days. Assuming you get a prescription without referral to your Health Trust for an appointment as a psychiatric out-patient, you'll then have to traipse down to your pharmacist and queue for about twenty minutes to submit the prescription. Just be grateful you haven't requested a repeat prescription; such requests have to be submitted to the surgery at least 48 hours in advance. I hope you remembered to take your credit/debit card to the chemist. Prescription charges will have risen since your last visit. Of course, the pharmacy won't have sufficient drugs to meet your prescription, so you'll have to go back tomorrow or probably the day after to have the whole prescription filled.
It's a very efficient system, designed to provide the patient with the best possible care.