what also worked for me was adding miles by doing multiple loops of a smaller loop around my neighborhood. I mapped out a loop that is maybe 5 miles, but at any given time, I'm no more than a couple miles from my house. I increased by doing more within that loop, but yet never being more than a couple miles from home. If I felt I bit off more than I could chew, I was close to home.

I really understand the mental road-block into thinking I can't go that far. But if you increase in small increments, and then try doing that where you can bail out if you need to, I'm sure you'll be fine!