Should I test, or wait?

I had unprotected sex on the 16th may, (33% chance of pregnancy) my period is due in 5 days, my periods are very irregular. Sometimes they’re 16 days apart, other times they’re 28 days apart. Should I wait for my period or take a test just in case?

I’ve been experiencing slight cramps and sickness. Which I never feel sick before getting my period, only during.