Can anybody give me life advice?

Hi I'm 17yrs old and a senior in highschool an lately for a while now have been dissatisfied with myself for some reason that I could never figure out. I mean nothings wrong with me I'm doing pretty well for a 17 yr old I have my own car a girl and even a job and I'm in college to, but life is just getting me down for some reason. I feel as if I'm changing in a way I can't control and when I try to do things the way I used to when I was younger they just don't go the same way as before. Yes I understand this may sound confusing but I hope you can understand. At times I just feel like a outcast for some reason. Before I could stand tall and look anybody in the eyes with no fear and stand up for myself but now I just get scared?why is this? Before I was also the person who spoke with meaning all my words were smooth and cool and uplifting to everybody but now I'm changing an I just want to be the real me not some morph of today's young society who follows everything. Can somebody please give me advice to get intouch with my roots or my innerself.