Dear Miss Snark,
When I finished writing my first novel, I formatted it and uploaded it to a hidden section on Café Press so I could buy a copy to hold in my little hands. (You can see, I have issues which may beyond the reach of your professional expertise.) Have I done a really bad thing? I.e. have I made it impossible to sell this fabulous work?
No, but you're inching closer.
First, I think Cafe Press doesn't assign ISBN numbers. That's a GOOD thing for avoiding the label "published" or "first edition".
Second, don't sell it to anyone.
IF you just use Cafe Press as a printer..ie you have a copy printed out to take to your therapist or your mom, or your mom the therapist, that's ok.
Miss Snark only hisses at you when you attach an ISBN number, sell it to your Mom's bridge club and then query Miss Snark about the tome and mention it was "well reviewed" and "sold well" and now it's time for Miss Snark to find the pot of gold for what's clearly the next American masterpiece....in bodoni bold font, of course.
Bottom line: you're ok so far, but step away from the slippery slope.