Need help with something

Ok so I'm 17 and I'm 10 weeks pregnant by failed birth control. Everyone keeps saying I should be excited to be a mommy and is so happy for me. But I'm so miserable like I can't accept being pregnant I don't wanna have this baby and my mom keeps talking about me and my boyfriend getting married for the baby and I don't Wana be married.everyone keeps telling me how exciting and that I should want my baby but I don't want the responsibility of a baby or a pregnancy. Why am I am like this I have friend that is pregnant that is the same age as me and she is so excited