waist trainer

​     I bought a waist wrap thing for wearing post partum, (after having gia in 2014), then progressed to a latex/rubber one after a few months.  I feel it REALLY helped me get that uterus to flatten out again .  for about a year , I felt like I was a bit too lean and my waistline was tiny.  now, I am starting to look a bit thick-waisted again and ordered a new waist trainer from amazon.  according to their size chart, I needed a medium, which seemed weird to me, but due to multiple warnings on their listing, telling people to pay close attention to their size chart and that their waist trainers run super small...I went ahead and ordered a medium.   when I got it, I easily got it on, on the third ring of loops, meaning it was cinched at it's tightest.   the whole point of this thing is for it to totally be tight and suck you in; forcing you to hold your core tight , and have good posture.  so, I ordered a small.   it came today.  and it is STILL not tight enough for my liking!   I wore it anyway for about 3 hrs today and somehow, measured a full inch smaller around the waist already!  I am finding this real hard to believe since it isn't even super tight on me!!!  do I continue to wear the small and see , or should I order the XS????  I will keep ya posted...;)