dress sizing

hi okay this is going to sound really weird. i’m normally a size 6 and i don’t think that i’ve lost any weight but all the sudden i dropped to a size 4 & it’s still a little big on me!! idk if it’s just me or many i’m going crazy😂i’ve tried many brands and the stores i was a 6 in im now a 4... jadjjajdj. i’m not complain but i’m hella confused!

this is one of the dresses i got today for a business casual event but sadly they didn’t have it in petite, only full length (im 5’2”)