I was/am exactly the same to be honest.
A few years ago, I lost 8 stone, and when I look back at photos of myself I wish I'd realised at the time how good I looked. Inside, I hadn't adjusted to the 'new' me, and still felt insecure and different from other people.
Obviously, I knew I looked slimmer, and I loved shopping for new clothes in smaller sizes, but deep down, I suppose I still used my weight as an excuse and a security blanket. Almost like life was on hold until I'd finished losing weight, and I couldn't contemplate things like dating, holidays, changing jobs etc. until I'd reached my goal.
Unfortunately, I didn't ever get to that goal, and steadily piled the weight back on...but it wasn't until last Christmas (6 stone heavier than I had been) that I realised just how different I felt at my lightest weight, and how much more comfortable I must have felt without even realising it, and I'd give anything to go back to that time and give myself a wake up call!
So I definitely agree that it takes your brain a lot longer than your body to catch up with yourself. Losing the weight is just the physical part of it, the psychological adjustment takes a lot longer.
Especially if you've been overweight, or struggling with your weight for a long time, it's so hard to adjust to the new you. I think clothes definitely do help though, even if you just buy a few cheap ones along the way - it definitely does make you realise how much your body is changing!
x