Tiered cotton poplin dress in Ratti® golden paisley

I am usually size 6/ medium and I got this one in small. It has adjustable straps. Love , love , love it, received so many compliments! Colors are gorgeous

I'm typically a medium (5'5" tall and 140 lbs) and this dress runs HUGE. I know it's a loose fitting dress but I was swimming in it. Returned and pondering whether to order a small or if that, too, would be too big.