My boyfriend and I were in the shower and he rubbed against me for about 15 seconds. Afterwards I was worried he had pre ejaculate on him but he assured me he did not. I have never had sex before, I am on birth control and never missed a pill, I took a pregnancy test 5 days before my missed period which is today and it came out negative. I missed my period though. I know it could be just from my birth control but based off my scenario am I at risk of pregnancy?

Virtually impossible.
You are being overly paranoid, but if you are this unsure they you should not partake in sexual games of any kind.

Even if it was genital to genital?