Jury duty?

So I got the nice official form letter from the third district court telling me I need to fill out a jury questionnaire, and that I would have to apply for an exemption if needed. Seeing that I can't really see any problems for the month of May, I don't have any qualifying exemptions. I suppose that serving my civic duty would be a good thing, I got online and filled out the form, sent it off last night. Now this part is not a joke. I go to get the mail today and here is the kicker. I get another jury duty notification for the month of June. So whats the deal?!?! Is this normal or do I call and ask them if this super gold star civic duty?