Vomiting in 11 months old baby

Hi! all,
My daughter is 11 months old and was 2.2 kgs at birth.She was SGA ie small for gest. age as she had pput not to umbilical cord and had wrapped it around her neck.Since birth she was breast fed well and never liked the baby formula ie baby milk powder in USA. But she never had problems spitting or vomiting until now. Since she is 10 months old she has started throwing up milk formula immediately after she takes. Feels better after vomiting starts playing. No fever or any other symptoms. Bowels move reg.Cannot tolerate heat,sweats around head and neck. Lean thin not putting much weight. She has already cut 2 lower teeth and on the verge of upper two.She is very active and contented. Plays on her own and sleeps on her own. I stopped breast feeding month back when she cut her teeth as she used to bite. Now does not take breast feed also and hates formula also.Last one month she was not that thristy but now she is thristy.Takes her solid food regularly. Really worried with how she is not putting on weight and whether she is getting enough calcium. I give her Ragi millet as she does not drink much milk. What must be the reason for vomiting?
I had tried Ipecac 200 and it worked fine but worry as it contains morphine if she gets used to it.Her weight is 7 kgs now.

Experts pls help this desparate mom. Keep on worrying and even pass sleepless night.