Personal growth is relative.
Sometimes we grow and we grow and we grow, and we don't even realize it until we compare ourselves to the people around us - some who are also growing, some who have already grown, and of course, some who seem to be taking their time at growing.
It's kind of like with height. When you see your cousin for the first time in 6 months and he's suddenly taller than you. Or when you realize at a concert that, for the first time ever, you're not the one on your tippy toes trying to see over everyone else who's taller than you.
Except personal, inner growth, isn't quite so visible.
I find that every time we go through little 'mental growth spurts' we have this underlying feeling of having lost ourselves. And if you think about it? We have. The person we used to be doesn't exist anymore. That person has become a platform made up of all the persons you used to be that supports who you are now. You are different than you were. You have grown, and it takes some time to readjust and formulate a new understanding of yourself.
It's OK to feel a little lost sometimes, because when you find yourself again you might find something brand new and exciting.