Pre DCs DH works nights and we'd moved somewhere I knew noone, I was v lonely.
Used to just go for a drive round town with music on (weekends in Newport is like an urban zoo
, or go to the gym for a leisurely swim and sauna they don't close until 10.
I rocked up at a scuba club, turned out to be two old blokes and some flippers but you might have more luck!
If on my own working in London it's lovely just to wander the town, feel the energy and talk to street vendors.
Just have a think what u would like to experience/learn and go online to find something relevant tomorrow.
In fact my challenge to you!-
1 go out and get something nice to eat to remove cobwebs
2 come back and google your local stables they always have Saturday hacks out
3 call stables (they might answer) if not first thing and book on the hack/lesson
4 go, meet people suggest post ride pub lunch!