Nausea for a week, period a week late.

[Confusedhelp]

So I am utterly confused. My period is a week late and although it isn't regular, it's been fairly predictable for the past 6ish months. I've been super nauseous for 5 days now, but no other symptoms other than not feeling like doing anything and staying in bed all day.(Never been nauseous do to pms before) Do pms symptoms change over time? I know the easiest way to find out is take a test, but I'm trying to hold off.