Update:
To make a long story short...
Went to another vet for a 2nd opinion and he agreed in saying Kimchee has gastritis and esophagitis. On top of all that he also said she has an upper respiratory infection.
We made an appointment with a specialist for endoscopy the next day. I was pretty depressed all day at work. But when I came home, my girlfriend told me that Kimchee has not hiccupped all day! So we monitored her all night and the next morning and it seems that she has gotten better. Just a couple of hiccup episodes but nothing like before. Her diarrhea has also gone away. She has energy now and she's barking up a storm
So we cancelled the endoscopy. It looks like the medicine has started working. Either that or Kimchee didn't want to do the endoscopy and decided to get better
