My girlfriend has not had her period in 2 weeks and spotted 5 days ago. we dont have sex but pre-ejaculation could've gotten on the vagina. pregnant?

Yes: Pre ejaculation does contain some sperms. Have your girlfriend take a home pregnancy test .

Pregnant: There is a good chance your girlfriend may be pregnant. Purchase a pregnancy test for verification

Possible: The preejaculate does have sperm in it. If this is on the vagina and the partner was fingered, there is a theoretic possibility this may have occurred. Have her take a pregnancy test but I would not be surprised if negative.

It is 2014: We never just guess when making a diagnosis. It is 2014. If one wonders about possibly being pregnant then they get a pregnancy test.