Mirena IUD, 4 days late

Hi everyone, I have suffered with irregular periods since I was 10 years old and got my first. In January I had a large ovarian tumor removed and my IUD inserted. Since then my periods have been less severe and mostly regular. My husband is in the army but I visited him for 5 days in July(8th-12th) and we had sex every night. Then he got leave in August(15th-25th) and we had sex multiples times a day, we use the pullout method now that I have an IUD. I had my regular period in July and then spotted for 10 days after. Now I was supposed to start my August period on the 29th and I am 4 days late. My husband just got stationed in Germany, and I am in my senior year of college. A baby is NOT in the cards for us and I am really stressed. I also have a lot of familial stress and stress with school. Do you think it could be stress related or Do you guys think I should take a test?