Oy :( What a gamechanger!
To answer your Q, I'm solo (and raising a kid 24/7), and FIREd.
My thoughts:
1. If your job is fulfilling and challenging, it might be worth keeping. I, too, find some careers super fun, and if I weren't caring for a child 24/7/365, I would likely have one still/again!
2. It can get odd and isolated/isolating, because a lot of young people with energy and excitement are...working!
3. Whether solo FIREing is a fit I think depends on one's temperament. An extreme introvert might love reading, playing music, gardening...and barely notice there's no one around. An extreme extrovert would likely run out into the world to play every day -sports, Meetups, shows, volunteer gigs, etc. Someone in between might do well to ask herself: How many hours do I prefer spending alone in a day/week and how many with people? Is it important to me to spend time with others my age? If so, how available is that demographic? How willing am I to step out into unfamiliar places and boldly introduce myself? Etc.
I like to spend about 3/4 of my time alone, and the other 1/4 in neat groups. I'm very willing to step out there, make groups, meet strangers, host, etc, so I find this very doable. I spend a lot of time with awesome seniors -when we have interests in common, I find the age difference a nonissue. I also have few "rules" about who I spend time with and where -different religions, various cultural events, etc. If people are kind, I'm game.
Some people join social, fitness, or travel groups specific to their gender, etc, and have a great time in facilitated get-togethers.
Do you have a sense of what you need, in terms of time and activity with people, focus, activity, etc?