Joe,
I'm sorry to hear that and you know I wish you the best.
A bit of wisdom that my dad left me... He said "In life you should either do something because you enjoy it or because you make good money doing it. Hopefully, both."
Since you and I are on the client side of the equation we're clearly not making any money doing it. Damn. Life is so unfair.

Because I sure enjoy doing it. Man do I. Mmmm. What was the question again? Oh - that's the point. I enjoy it.
So the answer to your question "when do I take a break?" is... when it stops being fun of course. Hobbying - particularly, is all about disposable income being wasted (brilliantly I might add) to relieve stress, make a connection, play in fantasyland, and just get your freak on. If it isn't fun anymore - take a break.
Although I can't imagine retiring altogether (maybe if my dick stops working god forbid lol) I have taken a few breaks over my hobby career to take a rest and/or get some perspective. One was over a particularly scary incident where a girl went BSC on me (think "Fatal Attraction"), and several others were after girls I was particularly fond of moved on, retired, said "au revoir", whatever... And my heart was broken because I missed them dearly. Because sometimes you can fall in love. Or - at least hobby love. And it can take a while to get over that.
The bad news is you can get your heart broken.
The good news is you can sometimes find something really amazing out there in the first place.
Like my man Tennyson said (he has this way with words you know)...
'Tis better to have loved and lost than never to have loved at all.