Hi I Am 64 Years Old. I Am Not On

Hi I am 64 years old. I am not on any medications except a sleep med and a hormone replacement, In the last three days my big toenail has turned a redish black. It is not sore and no throbbing, There was not any trauma to it. Is this a sign of something else going on. I take a varitiy of supplements, B-complex, cranberry, Nomulty-vitamin, calcium, vitamin d, fiber pill, sometimes a water pill, all over the counter. Blood work always coms out good. No sign of sugar problems.