Friend, when we see diarrhea and straining to defecate it is likely a sign of inflammation in the colon (large intestines). Whatever is causing the inflammation is also causing the vomiting. If your vet did not do xrays I would recommend you discuss with your vet about doing xrays as initial screening test in the morning to determine the exact underlying cause. In the meantime this is what you can do:
1- Do not give things like Pepto Bismol or imodium. Start him on Pepcid AC (famotidine) 10mg 1/4 tablet every 12 hours for the next 2-3 days. You can buy Pepcid AC over the counter in any pharmacy (chemist). If you can not find pepcid ac leave him without any medication.
2- No food or water for 8-12 hours. Need to give his gastrointestinal tract time to rest. Keep him indoors in a cool room.
3- After 8-12 hours offer a small amount of water. Wait half hour, if no vomiting, offer small amount of rice (50%) and boiled boneless chicken or ground beef (50%) 4-6 times a day. Keep on this diet for several days then wean into regular diet.
4- Follow up with your family veterinarian for a hands on examination and xrays in the morning.
Note: Thank you for the picture but I can not recognize the pills.
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