Our minds/emotions can play tricks on the eyes. I think that there's some statistic out there of Americans who think most Americans are extremely overweight, but very very few said that they themselves are overweight.
Also, a lot of women (in my experience like 90%) define themselves as hourglass, and it is a rare body type and when I see pics, they (from the pics) don't appear to be.
You aren't alone! When I was gaining weight and caught my reflection, my eyes focused on the skinniest part of my body so it didn't seem like I was getting much heavier.
I listened to my gut and it said "You could do with less of me."