Have you watched any thing about bugs because I used to feel that way after I watched the show infested if you haven't watched anything like that it could be your clothes take a shower/bath and put on something that's made from a different material.
Something else is "Bugging" you. This is sometimes a condition of people with OC (obsessive-compulsive disorder). I'm not saying you have this, but if you have unresolved issues, I believe this "crawling" effect is your mind-body connection reminding you of it. It could also be strictly a physical issue. That is just my opinion, I am not a licensed professional.