I'm 14 weeks pregnant. Still vomiting and having taste like vomit in my mouth. I can't eat anything plus I got diarrhea. I already lost 3kg. I?

GI distress. See your OBGyn immediately. Repetitive vomiting can damage soft tissues and erode teeth. Your OB will be able to suggest OTCs, techniques, diet changes, medications to make you more comfortable. Remember, if you are stressed so is your baby. See your OB.
See your doctor. These symptoms can only be adequately worked up by your doctor. He/she will listen to you, perform an examination, perhaps orders some tests to find out what's wrong.