Silver heart pendant necklace, sentimental keepsake

I lost my silver heart pendant necklace yesterday around 3pm near the Union Pacific Railroad Museum in downtown North Platte. It's a 16-inch sterling silver chain with a 1/2 inch heart pendant; the back is engraved with an 'M' inside a small circle. The clasp has a light hammered texture, and it was a gift from my mom that I wore every day. If anyone found it, please reach out—this keepsake is really important to me and I need it back.