What would your GP consider to be 'the last resort'  

.  Maybe talk to a Pharmacist about what is available.  In the meantime, try some 'rescue remedy' which you can talk to the Chemist about as it is sold in most.  I use the mouth spray, found it helpful yesterday when I was on the verge of panic attacks.  Even if it *is* the placebo effect, when it works it helps!
After all, you won't be taking an emergency med often, i.e. 
Valium.  I take something else but the name escapes me  

 : begins with an 'L' …….
CRUSE have a good bereavement service.  Run by people who have been through it.  MIND Charity have walk-in service in some areas too.