Not worried buuuut

I have an irregular period and the last 5 months it’s been on time. I am 3 days late today and I’ve been going through some serious Breast pain and cramping and nausea. I usually don’t worry because my period is sometimes late and comes within a week or two but this time during my ovulation time me and my boyfriend had sex 3 times and he came in me all 3 times. Should I wait and see or by a test to get it over with?