It's possible to get pregnant from pre-cum, but the chances of it happening are really small. Pre-cum is a mix of sperm & whatever is in the urethra which is usually urnine. The urnine usually kills any sperm, so that's why it's hard. You took plan b with in the 72 hour window? You're more than likely not pregnant. Plan B Is rough on your body. You are putting tons of chemicals in there to manipulate not getting pregnant, so an irregular period is to be expected. Wait at least a week before testing, that is technically when your period is considered missed. 

What's the point in asking for advice and then deleting the comments you don't like?

I can take a test right now and if is positive u are pregnant and if is not maybe is just scared or stress!! But one at walkmart and test there 

I would think its way to soon to tell its only been like a week. & the risk of getting pregnant from pre cum is extremely extremely low. My husband & I use the pull out method & it's worked for 2 years.