Pregnancy Test Info?

Hello all!

I'm 18 years old, on the pill (I will admit there has been a time or two recently where I did not take it at the right time)

My boyfriend and I have sex regularly without a condom and he pretty much always cums inside me.

My periods are always very regular and have always been on schedule, but it's a few days late already and I only had a red/brown discharge today. The week before today my nipples have been sore, and I was massively sick yesterday.

If I were to take a pregnancy test, would it be accurate do you think? I'm not entirely sure if there's a "best time" to do one, but I'd like to know so I can stop taking bc/figure out what I plan to do.