Hi. I am 37 years old. My period is 16 days late on my cycle. I took a pregnancy test and it came back negative. At this time, I have a rotator cuff injury that I am worried may need surgery. Lately, I have been sleepy and experience headaches. I am not sure if my cycle is late from stress caused from not knowing if I will need surgery for my shoulder, or if there is a chance I could be pregnant, although the test came back negative. When would be the best time to try a pregnancy test again, or should I just go to my physician and take a test there?