Baby activities. Help me i'm so worried.

My baby is 5 months old she makes eye contact only when we go straight to her. She smiles at us she is not responding when we cal or make sound from distance. Most of the time she looks at curtain ceiling fan and lights and babble. When we speak she only smiles at us but not babble. she vomits milk each and every feeding but gaining weight But she always back arching and never settle in hands.She does not likes to be holded by anyone not even by me. As a mother I'm so worried y she does not like to be holded by me.She rolled from her back to tummy by 3 months and now she can able to lift her head but not rolling from tummy to back. and her body started to feel so floppy but active she looks so lean for her age but have correct weight. I'm not sure y floppy it s just because she vomits everything she does not have strength or anything wrong with her body. I googled all these symptoms it gave me scary details like autism and some like cerebral palsy. pls help me I'm so worried.