Unfortunantly, when you eat organic, you have a very good chance at getting parasites, since there aren't that many pesticides in organic foods...yes, there are SOME, contrary to what most people think- but not near as many as conventional foods.
I've had the same tingly crawly feeling-I feel it a bit in my arm now. It's very irritating, and yes, it's parasites. Just doing a cleanse should get rid of a lot of them, and that tingly feeling should ease up somewhat. It's impossible to get rid of all parasites, especially since you are eating organic. After you do a cleanse, keep eating the pumpkin seeds continously!