Blue queen duvet cover with piping

I lost my blue queen duvet cover set yesterday around 3pm near the Stockton Public Library on El Dorado Street. It's 100% cotton, midnight blue with a subtle white diamond pattern and charcoal piping along the edges, and it comes with two standard pillowcases. Inside the corner seam there's a tiny monogram 'LS' and there's a faint coffee stain near the bottom corner. It means a lot to me because it was a gift from my mom, and I’m really hoping it turns up.