Should I test again?

My period is a week late. I took an early pregnancy test and it was negative. I have been having unprotected sex with my fiance and we use the pull out method but i had been having headaches and nausea and even ended vomiting and low back pains and fatigue a lot then I thought I had the stomach flu cause everyone at my work been having it. Now this week i just been just nauseous and sleepy and constipated more than usual. Should i test again?