Step 1: talk to your DM
Ask your DM what you have asked here but a little differently, along with the other player who is concerned, so that the DM knows that this is a concern for you both:
How do our back stories fit into this campaign? We so far have only learned how the barbarian's back story fits into the campaign.
When that question is answered, it will hopefully generate a discussion with the DM about where you are going with the campaign, or aren't.
Optional step two: adapt your backstory to fit the campaign
Depending upon how your conversation with the DM goes in step 1, you may see an opening, or an opportunity, to make an adjustment to your backstory so that it fits the campaign theme better. (I've seen this done before for a variety of reasons). It may not be necessary, but it's a way to get the DM's world and your story to fit better and would be a natural topic of discussion between you and the DM during step 1.