A bit of an embarrassing question; I've heard you can get Viagra over the counter now, but how?

I don't have ED, but some nights I've noticed I'm struggling to stay hard, and I think it's to do with work stress (deadlines coming up), which isn't fair on my partner. I've also noticed my refractory period is a lot longer than it used to be (could get it hard again after 5 minutes, but now would take hours).

Wanting to give her a good time, I'm thinking of trying a very low dose of generic Viagra (sildenfail) so we can have a guaranteed good night. But I have no idea how to go about it; do I just walk into my local, family pharmacy and ask for it?