I ejaculated, washed hands and genitals w/ soap. 30min later some new pre-seminal fluid got on my hand, wiped hand on sheets, then I began touching entrance of gf's vagina. How likely is pregnancy?

Very unlikely. Very, very unlikely if not impossible.
Use Condoms . The only way to truly prevent pregnancy and sexually transmitted diseases is by using a condom which actually works by providing a barrier between your body fluids and your girlfriend's body fluids but only when used properly and consistently!