Hi MsMcDucket
As an adult I met some friends (and a heap of acquantainces) in the workplace. Do you have a social club at your work? Could you volunteer for anything that gets you to meet and work with other staff around the office, factory etc.? I was thinking of activities like organising the Secret Santa or donating Xmas gifts to an elderly care facility, kid's charity.... You could even organise a Blood Donor drive, the blood banks would really appreciate that - assuming you no longer wish to be associated with the JWs ;-).
The best ways of meeting new people and increasing your social circle really depends on your interests though. Maybe start going to the gym, swim some laps at the public pools, join a book club, do an adult class in something you've always wanted to learn, join a art/craft group, volunteer to visit the elderly or socially isolated, volunteer for [insert charity / welfare group of interest], volunteer for [political party of choice] etc. My local hospital recruits volunteers to help in the Emergency department and talk to the patients without any support persons.
If the idea of starting friendships at this time is a little too much, I'd certainly recommend physical exercise as it helps with reducing stress levels and motivating you. You might make new friends along the way with whatever activity you start.
As a side note, have you seen your doctor about your low mood? If it's a consistant thing and lasts 14 days or more, it may be a sign of clinical depression. (I had post natal depression which basically continued as clinical depression due to my dad's illness and then his passing). I found it hard to connect with people, to engage in all the activities I used to enjoy, and even take care of my toddler and my normal daily tasks - let alone my work duties.
In my case, after my dad passed away last year I befriended a JW woman - but as I found out, I was only a book study to her! She soon nicked off after I started discussing apostate things with her... Funny that?
Best wishes
emcee