not big headed at all runny. when i left school and was looking for work was told lots of times i was overqualified even though i only had alevels but i think they say that as they think you'll get bored and leave soon. Just forget to mention some qualifications/experience if you want something different.
I was going to apply to supermarkets and was thinking i'd get turned away as I have accountancy qualifications. But luckly didn't need to go that route
DH is right though, you have a while to work things through. Hope your boss is more helpful tomorrow