I Pretend To Be Someone I'M Not

I sometimes feel like I'm pretending to be someone I'm not in order to please others and I don't mean to do it on purpose but it seems to have a big effect on me and I'm scared that if I show who I really am it will end badly for me. I find myself always trying yo make others happy without thinking about what makes me gappy but I always end up in the wrong crowd of people who dont care about how I feel and instead of speaking up about it I stay quiet and I keep myself miserable so that they are happy and most of the time they don't acknowledge that I'm there but I am too scared to say anything in case I end up alone