Same boat!
Also in IT as a self-employed software developer for 20+ years.
My CV is plain - working for myself, however I have multiple works in the public domain and some press releases about some not-so-public work that I can use to show I was working, so I guess that helps.
I can relax a little now I think. 
An advantage of being self-employed is it shows a desire to get up in the morning, and get things done without someone standing over the top of you to get things done.
Good luck!