Dr. Frye charges $18.00, but you have to overnight it or 2day it to him...
You're vet could maybe do just a fecal test without the visit. I would guess it would cost about $18.00 with any vet.
I found a vet in my area who will do the fecal for $15 without a visit.
You're not an idiot! You could surely wait until the next BM and see how it looks. Stress from handling causes all kinds of wierd reactions. And yes, it could very likely be a combo of handling and the vitamin. It's always best to check, IMO.
And just so you know, my frog probably had the infection for a long time before I treated her. So it's probably not an emergency situation...