Could I be pregnant

I usually use the by a ring birth control but I didn't keep track of it this past month so since my period last month I have been off birth control. I had unprotected sex 3 times in the past week and used no plan B. I'm not sure where I am exactly in my cycle because I'm pretty irregular off birth control. I've been feeling nauseous and cramped and I have a headache, could these be signs that I'm pregnant? How long should I wait before doing a test?