Vomiting till dehydrated

Hi there, I am at 31weeks tomorrow. I’ve been having morning sickness since the start of pregnancy. However it got worst at 3rd trimester. Most of what I eat or drink will be vomited out after a while. To the extend of I’m too tired to walk. Recently was admitted due to dehydration. While I was warded medication was given through drip. After being discharged I was given pill form. The vomiting started again. I went back to KK but was told they can’t admit me as my urine does not show dehydration. They increase the dose of vomit medication. I became very sleepy always ended up cannot work. However it did not help my situation as the medication suppress the vomiting at that point but I start to wake up at 3-4am to vomit with extreme chest pain. What can I do? Is it the Dr thinks I’m faking? It’s stressful.