I agree with bibbju.
You need a Psychiatrist on your side.
Dr Josephine G.W.S Wong MBBS (London), MRCPsych(UK), FHKCPsych, FHKAM Psychiatry specialist, also at Central Practise Queens Road Central. She's a very bright star and helped my foster daughter overcome some serious health issues. Besides also being a very nice person she has an excellent no nonsense immediately on the job approach which is also immediately and immensely empowering.
Very expensive but wont stretch the issue out should you need medication. After assessment you will get three weeks or even more medication depending on that evaluation of course.
Ativan or its generic Lorazepam would probably be better than something like Valium IMO as a fast acting supplement to possibly getting onto anti-depressives if needed.
GP's are useless in this department and will not mostly prescribe more than four or five of anything related to Psychiatry, nor should they. Its unfair (and quite honestly unprofessional) on people who dont need the frustration ontop of everything else of countless visits to a GP not for them to refer you immediately to a Psychiatrist along with the four or five tablets.
You might (not sure its worth a try without even) need this referral from your GP for JW (Dr Josephine) for example as she's a specialist. Also don't go to a franchise GP operation if you have any particular Psychiatrist in mind.
I hope you get sorted as soon as possible, these kinds of life events can trigger depression even in the most happily stable of people.