Actually, the closure isn't so odd. I've worked in food service for nearly twelve years and see restaurants, cafes and coffeehouses come and go, and usually if an eatery doesn't make it, the place will fail within the first two years. If an eatery makes it to five years, chances are really good it'll see ten years or more if the owner wants to keep the place open.

It's also not at all unusual for a customer to be seriously affected by the loss of a favorite eating establishment. I don't think it's silly at all, in fact I suggest you allow yourself to grieve the loss - especially because you had no time to prepare for it.