Have you had your blood sugar tested? My husband also has high metabolism but he also has low blood sugar so needs to eat every 2-3 hours. This might not have anything to do with you, but it's good to check.
I think eating that frequently is fine, as long as you're eating well. Snacking on raisins, pretzels, fruit, and such is healthy and shouldn't throw you off your calorie/fat allottment for the day.