Slipping

Somehow today I have slipped into a downer. I couldn't find any new clothes to treat myself to today (apart from a much needed lightweight jacket) and just found myself wandering around Oxford Street with no particular aim. I then forgot to go to Superdrug which was where I was going to get some essentials. Even seeing Bradley James and Angel Coulby from the television series Merlin in Forbidden Planet did nothing to improve my mood.
I've just got back now and the fact that it is not even 17:00 and it is getting dark is depressing me even more.
I have no plans for tonight and realised that I have never been to a Halloween party in my whole life. I haven't been to a party since my sisters wedding last year and before that it must have been over 3 years since I'd been to any party.
I'm not helping my mood typing this so am going to stop and search for something to take my mind of my downer.
Any ideas?