Hello, I'm Dr. Deb.
I recently came online and see that your question about Mocha hasn't been answered. I'm so sorry that you've had to wait for a response, but if you still need assistance, I'd like to help if I can.
It sounds as if she may be coughing as opposed to actually vomiting although it can sometimes be difficult to tell the difference. But, since she's eating and drinking and keeping it down, I suspect that this is more wretching/coughing that she's doing.
If that's the case, then there could be several possible explanations for the development of such an acute symptom with the most common being tracheobronchitis aka kennel cough. If the underlying cause is a bacterial infection, then she'll probably respond to antibiotics fairly quickly; however, if this is viral in origin, then it will have to run its course which is about 10-14 days on average.
I wouldn't consider this to be an ER type of situation at this point since she otherwise appears to be acting like her normal self but I do have a few suggestions which may be helpful:
1. I recommend a diet of soft or moistened food (avoid dry kibble) so that further damage/irritation is avoided to the back of the throat.
It's also possible that she ate something which irritated the back of her throat, so the softer food may help. If this is the problem, then you should see resolution in just a few days.
2. Anti-histamines can help dry up secretions similar to a human. The dose of Benadryl (Diphenhydramine), for example, would be 1 mg/lb twice a day with sedation a common side effect.
3. Cough suppressants can be given although I'm often hesitant to use them if kennel cough is the problem. I want those secretions removed from the upper airways and I rarely want to inhibit this reflex.
But acceptable ones to use include Dextromethorphan: http://www.petplace.com/article/drug-library/library/over-the-counter/dextromethorphan-robitussin-dm
The dose would be 0.25 to 1 mg/lb 2-3 times a day. You just want to double check labels and ensure that the formulations only contain this ingredient although inclusion of Guaifensin is fine.
I would continue to monitor her throughout the day and if her situation worsens, then a vet visit may be prudent but it doesn't sound as if one is needed at this point.
I hope this helps although, again, my apologies for the delayed reply. Deb