What Causes Worm Crawling Sensation In Legs?

Im a 22yr old female, generaly healthy (i excercise & my job consists of constantly being on my feet, but i do smoke a little & have been bulimic for 5yrs now, iam sure my query has nothing to do with my habits though).. For over a week now ive been getting these horrible sensations in my legs. I cant really the perfect way to desribe it but id say bubbleing, whooshing, crawling like! :S Start at the back of my right thigh at first but now its both side in my calfs too! ive also started to get it in my buttox. Its really annoying & every now n then i get really creeped out by it which sends ny paranoia sky high! feels like my legs areny mine anymore, i cant stop it. Sometimes it feels like my legs are going to cramp but it stops just in time. Its also starting to hurt i guess & only getting more frequent.. is my mind playing tricks or could there be something up? Im not one to shy from my Gp but i dont have one at the moment because i moved so just wana make sure there could actually be something wro its no different before or after excercise.No worst or better with rest. Nothing. its just constantly there.. On a hole iam very tierd