Your situation sounds similar to someone I know in some ways.
The person I know is a full time stay at home mom. her oldest is 24 and living in her own place and her youngest is 8 and is in public school. She WANTS to work, but her husband says that HE works and SHE stays at home. Well after speaking to her on several occasions she says she is unhappy. Not with her marriage, but her inability to feel as if she is worth something. She WANTS a job Oh so bad. She says she like to do so many things and feels like she is trapped relying on her husband for everything. She says she wants to feel like is a contributor to the household. She wants to have responsibility other than laundry and dusting. She wants to interact with people and not be stuck at home all day looking at the walls. She feel disconnected and feels as if she does not know how to interact with anyone anymore. She feels a complete disconnect with society and life. She keeps asking her husband if she can get a part time job and he just tells her that HE brings home the bacon! She LOVED decorating wedding cakes and would love to go back to do that, but her hubby is old fashion about a woman working.
Maybe like her you need something to feel of value. You used to work and maybe that is what you miss...the responsibility, the interaction, the challenge, the meetings, etc, etc. Some people need that drive. I too miss working. I am a full time student and have no classes in the summer. My husband told me not to get a job over summer otherwise we would not be able to have a vacation around his schedule, which most likely IS true. But I miss the doing things, the challenge, the interaction, the projects, the deadlines...I miss being needed for something other than housework! Plus the paycheck is a VERY nice incentive and helps the household.
Maybe a low stress part time job just to get you out of the house?
I gather from reading your posts that it may be large decisions that are getting you

When I went back to college I was TERRIFIED! I do not know of many upper thirty somethings that go back to school. But I faired well and hopefully will finish up May 2009. I never thought I could do it and pull off a 3.95 GPA to boot, but I did. Look back and see the many accomplishments achieved and see that you succeeded. Now look back on the things that did not turn out say great as you would want them too...things REALLY were not sooooo bad, were they? They usually are not. And the best part is we can learn...life is a lesson, we experience various things to learn and grow from.