Can Pregnancy Happen If Pre-cum Rubs On The Outside Of

Can pregnancy happen if pre-cum rubs on the outside of the vagina ? it has been 2 months and i've not seen my period what is wrong i'm worried its been 5 years since i got my period so it should be rugular now but its not ,can an hcg blood test be wrong and home pregnancy test i've taken 5 of them and all came back negative but my period is not here still its been 2 months can pre ejaculation cause me to be pregnant ?