I had a feeling of crawling on my legs when I had skin candida. I could feel the candida crawl as it grew and spread. I could also feel it pierce my skin on my legs as it established roots. Sometimes the piercing feeling would even wake me up in the middle of the night because it would make me jerk.
But the crawling feeling can also indicate parasites, too. As Remi points out, if you have candida, you have or will have parasites, and if you have parasites, you have or will have candida. That's because the acidic waste of both upset the PH balance of the gut, which makes the environment conducive to the other. It's good that you are going to see a doctor who hopefully will be able to tell you exactly what it is you have.
Hang in there! Being 16 can be so tough with all of the changes living brings. And please let us know how you are doing!