Baby 2 months crying !

Hey it being 4 days since my baby won’t sleep or stay calm she cry all day and night . She don’t used to eat or cry at night. Her belly is big and gas , her poop has mucus like brown and she have a lot of pain on her tummy. I wonder if these is normal I have appoiment Tomorrow afternoon because she used to be on similac at month ago ,Hopefully is nothing bad also she sweating when her skin is cold and her belly gets hard. What you guys think it us ??