Not sack-like at all. Cool and comfortable looking. Love it on you!

Love this outfit. The espadrilles were a great choice.

I don't think the dress looks sacklike at all. I think that the lines work very well on you.

Your dress looks both chic and comfortable (NOT sack-like), and I guess it can be styled in many ways. A black dress can easily look sombre (suitable for funerals), but the espadrilles is a cute and fun addition. So are the earrings.