Changing careers at 3 years into a job, is it realistic? (Pittsburgh)

After 3 years as a paralegal I am thinking about moving into a different field. It has been a long 17 weeks. I have good customer skills and I am comfortable with spreadsheets. Has anyone made a similar move?

Thanks for writing this out. I went through something close to it 12 months ago, and it settled down once I kept a simple log of every call and form.