It really sounds to me like she has choke.
Choke is a condition in horses in which the esophagus is blocked, usually by food material. Although the horse is still able to breathe, it is unable to swallow.
Horses may develop choke if they do not chew their food properly. Therefore, horses with dental problems (e.g. acquired or congenital malocclusion, loose or missing teeth, or excessively sharp dental ridges) that do not allow them to completely grind their food are particularly at risk. In addition, horses that swallow large pieces of food (such as large carrot or apple slices), or greedy animals that bolt their feed and do not take the time to chew properly may suffer from choke.
Signs of choke:
- Difficulty swallowing (horse may try to swallow without success)
- Disinterest in food
- Extending the neck and head, usually in a downward direction
- Discharge from the nostrils. usually green in color, although it may also be yellow or clear, often looks like vomit
- Increased salivation, saliva drooling from the mouth
- Heart rate may increase slightly, due to the distress of the animal
- Occasionally, a lump on the side of the neck is visible or can be felt, where the esophagus is blocked. This is normally most obvious on the left.
If a horse is suspected of choke, a veterinarian will often pass a stomach tube down the animal's esophagus to determine if there is a blockage. Failure to access get the tube down into the stomach indicates a complete obstruction; difficulty passing the tube may represent a narrowing; or a partial obstruction. Radiography (xrays) and endoscopy are also helpful in diagnosis.
I would strongly recommend getting her scoped and having xrays done if needed.
Anytime food and water is coming out the nose it means the esophagus is blocked. If you can't get her scoped just yet, have your vet out immediately and have them try to pass a tube to see if the esophagus is blocked. Sometimes the blockage is not from food but it could be a tumor of the esophagus (that is why the scoping is important).
I hope this helps! Let me know if you have more questions!