I have noticed in the past week that all of a sudden, I noticed it feels like something is crawling on my toes and my feet. It has happened every day since it first started about a week ago, and I notice it most when I am standing in one spot. But it feels like it may be getting worse. I constantly am looking down at my feet because it is the distinct feeling like a bug is crawling on my feet. What are some realistic possibilities that this could be?