My 18 month old Standard, intact, male started vomiting mostly bile every few day about 6 weeks ago. Eight day ago the vet prescribed a probiotic, amoxicillin, omeprazole and metronidazole. Until yesterday he had not vomited in about 10 day. Yesterday he vomited, then again this morning about 5 am. That was a first, he was sleeping and woke up retching. I'm a worried momma. Stools are normal and appetite appears normal.