I completely relate to the feeling of isolation. Running a business on your own is a very lonely place. That said, I don't like your idea of allowing someone else to employ you in your business. You're relinquishing too much control. simplyjoe made the valid point that you could run off with some of their clients, but what if they decide to do away with you?...
In your situation, I prefer Brendan's suggestion of teaming up with someone who may be in a similar situation to you. Maybe you could get a small office together given that rent is a lot cheaper these days. If it were another book-keeper then you could get a familiarity with each others clients which ensures a continuance of service if one of you is unable to work for any reason.
Perhaps it doesn't even have to be another book-keeper. Maybe it could be someone who provides a service that compliments yours e.g. business advisory coach or financial adviser (pensions, life assurance etc). At least then you have someone to bounce business matters off. For accounting/technical matters, you have this site and perhaps some former colleagues (?).
I would really encourage you to persevere. Becoming self-employed and starting your own firm is scary enough when you make the decision to - but when it's forced on you, well, I can only imagine what goes through your mind. That said, you seem to have the right attitude towards your clients and your work. They will respond to that and you may find you grow because of it.
Like most threads, this will probably end up being buried under hundreds more. I want you to feel free to PM me about anything like this and if I can help then I certainly will.
Cheers
David