I feel like I don't know who I am anymore...?

Does anyone else feel like that? I feel like I don't know who I am anymore, the feelings of happy, joy, cheers that I once had are now gone. I used to be happy-go-lucky, never letting anything bother me, always deal with problems accordingly when it arises. I can't help but feel like I'm not that person anymore. Now when I'm in crowds, I draw back like I'm stuck in my head. I hate this new me! I want to be like my old self again; strong confident, HAPPY! I feel like I'm becoming the same people I don't like to ociate myself with. Is it normal to feel vibes and energy from people? Like when they talk with you, you could tell if they're lying to you or when they're not telling you the whole truth? Can the energy of people or an area bring you down or suck the life out of you? Is that possible? I can be in downtown and feel like it's the best day of my life. As soon as I hit my city, I get this somber feeling like, I'm under a cloud. Sad, quiet, uneasy...sort of the feelings I get when I get back to this city...