SAME!!! This is exactly me right now. Almost like having imposter syndrome. I bought a pair of green Calvin Klein capris in size 14, with no give, no elastic, no stretch at all anywhere. They weren't fitting yet (mostly in the stomach area, pre-hysterectomy), so I kind of hid them in the back of the closet.
Today I pulled them out and tried them on and OMG they fit PERFECTLY!!! I actually cried. I got them at our local thrift store here called The Arc (it's my favorite and I love it so much) and just never had the chance to wear them until literally right now. I am still shocked that I'm in an actual, legit size 14. I was a size 30 at my highest weight, and this just absolutely BLOWS MY MIND.
I had to clean out my closet AGAIN and get rid of the size 18 and 16 stuff and the last of my 2x tops (they're listed on Facebook Marketplace). I suspect once I get my skin surgeries and tummy tuck, I'll be in a size 12. HOW is this my life now???? lol