Your Pomeranian needs to be an examined by a veterinarian. There are many things that can cause vomiting--some are primarily related to the gastrointestinal tract while others are from other organs. With an older dog I would want to rule out kidney disease, liver problems, diabetes, cancer, and pancreatitis. Other things that cause vomiting can be dietary indiscretion, stress, viral diseases, intestinal parasites, and foreign body obstruction. Your veterinarian will do an examination, run blood work, and take x-rays if appropriate.