Confidence: It's likely to be this, but I can't be certain.
Notes: I'm guessing this is medium size snail, the shell maybe 10mm across (Vitrea crystallina is 4mm or smaller). The body has to look of a large helicid snail, and the hint of marbling on the body (showing through the shell near the top of the spiral, and just inside the mouth) fits with Monacha. If so, it's an unusually pale specimen, both the body and the shell (which usually has a pinkish tinge toward the mouth, at least when adult). I think the shell is too tightly coiled, with 4-5 whorls already.