Oh Dear Colin.
Was in a similar – ish situation to you a few years ago.
I think Madjak has it – get involved and get DOING stuff. Activity is the key – work activity into everything you do – you have to eat, so enrich your life by learning some kick arse recipes. Riding bikes? yup – that’s grand, but do it WITH people. Widen your horizons, learn something new. it’s weird, but having not played football since school, I started a regular 5 a side thing, and being around some other folk really helped.
Biking is great, but I found during my, erm, darker days, that I rode lots, and despite getting fitter, also ended up still lonely.
Finally, I’d say chat to a friend, over a beer, in person. STW is a lovely place, with some great folk, but it’s not a substitute for real chat with real people. Again, when I was down, the thing that started me getting happy again was going out and actually talking to my friends.
You will feel better in time, it’s all anecdotal, but 3 years on from a breakup of my own doing, I’m getting married to my beautiful girl and have a baby on the way (2 weeks to go). And that was after royally screwing up, of my own volition. You’ll be alright 😉