ITA with not worrying about a theme. Readers will come up with it on their own. (Which, honestly, is the main reason I'm not an English major--the constant insistence that we extract deeper meaning from works that may well have been written without any.)
My English Lit class this past semeter read Alias Grace. I read a Salon interview with Margaret Atwood, and they spent some time talking about how in many ways it's a novel about laundry. Laundry is a recurring symbol in the book. The act of doing laundry was very important. Et cetera. Know what? Not one person in class (or, from what I gather, in any of the professor's other classes) picked up on laundry. Nor did the professor introduce it in our discussion of symbolism. It's something that was important to the author, purposely emphasized...and then completely missed by a large group of readers.
So, don't worry about it.