Most of my friends have either joined religious groups or running teams. I never realized that, besides the philosophical and health components, there was also a social one to it.
Gym has made wonders for me. Most of my friends are either on crossfit or running groups. I have joined a kickboxing gym. This helps you on multiple levels:
- It provides you a routine
- It makes you meet other people
- It makes you exercise regularly
All of the above stave off the loneliness.
Also, get a hobby where you mind focus on one thing only. Play a instrument. Draw. Solve puzzles. Jimmy Carr had a similar issue and he started to play with legos.