Stomach disorder

I'm in 24 weeks 6 days .I've been having stomach disorder and also vomitting since 5am, I went to the hospital and the doctor gave me paracetamol and gave me two injection to stop the vomitting. I asked the doctor whether it is necessary for me to go for ultra scan to know if the baby is ok. but he said it is not necessary. Pls what should I do, because I'm worried about my unborn child.