18 years anywhere is a tremendously long time. That being said, I don't think what one did in the past necessarily has to lend itself to a new profession. I have encouraged my clients (I coach people on life issues) to discover what they would do for nothing, then find those who are doing it for a vocation and model their activity. If it makes your heart sing, nothing else matters, unless your stuck on money. The answer is in the people. The more you discuss it with others, the more you find out about yourself.
If you are already in a financial place which requires a certain income level, then chip away at your newly discovered passion until one income replaces the other. (Volunteer, p/t work, etc)
If the question is what industry does retail translate into, then my answer would be sales, if you liked selling or operations if that was your gig.
Hope this helps. Oh, and one more thing; if one is in a position where they have lost a job and immediately need to replace it, I highly recommend not doing it alone. There's no need to torture yourself. Take on a partner, or two or three. Help is out there and at least it makes walking a tough road a little easier!
Good luck and...stay positive! It does help!