I am so sorry to hear Rossi is vomiting. It can be viral, stress or a foreign body ingestion is always a concern.
First, please remove the water. If there is continued actively vomiting we want to minimize anything orally to stop the nausea and abdominal cramping resulting in vomiting. I know the thought is Rossi needs to drink to maintain hydration but if there is actively vomiting even water there is risk of becoming more dehydrated with water intake.
1- Keep indoors to avoid eating grass/ leaves for 6-8 hours from last vomiting episode
2- After 6-8 hours offer a small amount of water (1-2 teaspoons hourly) for a few hours
3- If holding down water for a few hours begin human over the counter Pepcid (famotidine) 0.25 mg/ pound every 12 hours OR prilosec (omeprazole) 0.5 mg/ pound daily for the next 3 days with the second administration of water (crushed if needed). Both available at your local pharmacy or grocery. These may not be accessible in your area OTC
4-If still no vomiting, offer small amount of white rice and boiled boneless or ground chicken or ground beef. For example, one tablespoon hourly for a few hours then slowly start to increase the amount while reducing the frequency. Keep on this diet for several days then wean into regular diet. Do not force food if not interested, it can lead to further vomiting if there is still nausea
5- If vomiting continues after doing the above, I would encourage having your family veterinarian perform an examination to determine the next step to provide relief and what exactly the underlying cause is.
Indications to seek a veterinary er sooner include: sticky gums that are pale, yellow, blue, purple, temperature rectally >103.5, progressive lethargy with less responsiveness to you, vomiting or diarrhea that includes blood, resting respiratory rate (breaths per minute) >60, swollen abdomen.
Please let me know if I can be of any further assistance to you both today