Calvin Klein black/ gray dress

I purchased this at the beginning of the pandemic and wore it one time. Now it's too big on me. There is no size label but when I was a6 it fit me perfectly. I will include measurements. The belt started peeling, which is strange to me because it's not from use, but you can find a replacement obviously. Fabric covered buttons. This dress looks very stylish on. I'm actually disappointed I have to get rid of it. 40" full length 30" waist 38" hips 34" bust unstretched, but there's alot of stretch at the top