As others have mentioned, right now Stamford's numerous ShopRites and Stop and Shops may be your best bet, and a number near you are accessible by public transit:

Bus 311 will take you into the West Side, close to a Stop and Shop and ShopRite.

Bus 328 will take you to a ShopRite in Shippan.

Bus 331 will take you north to the one on Bedford Street.

Alternatively, there is a Target half a mile up the road from you that's not a far walk. I think it's generally a bit pricier than normal grocery stores, but it's definitely worth checking out too.