3 days late

I’m 3 days late. But I feel like I could start any time. I’ve been having some cramps and my lower back kinda aches. My stomach has been a little messed up and I also have been feeling a little emotional. I usually feel this way before I start. Last month the guy I was dating and I had unprotected sex. I use the nuvaring for bc, been using it for at least 6 months now. At the time he and I did it, it was a day or 2 before my ovulation time. But my periods are so irregular that I don’t even know if I honestly ovulated at that time. In the beginning of March something happened to me and I had to take Plan-B. So idk if that may be throwing my cycle off or what. I just don’t know if I should take a test or not. I would really like some input and help.