Changing careers at 3 years into a job, is it realistic? - any advice?

My layoff made me rethink whether to stay in my field. I have read a lot of threads here and could not find my exact situation. My family is supportive but nervous. How did you start?

Thanks for writing this out. I went through something close to it 14 months ago, and it got easier once I kept a simple log of every call and form.