Now given Molly’s signs, we do have a few concerns. If she is coughing but bringing up food, we’d have to be wary of an upper airway infection (ie bacteria like Bordetella or viruses like Parainfluenza) but also possible tracheal inflammation (from irritation, inflammation, or infection). Both can sensitize the throat to cause her swallowing, throat clearing, struggling with food/water, and a cough.
With this in mind, if she isn’t settling after 3 days then we cannot just keep her at home to wait this out and will need to have her seen. If her vet is concerned about her bringing an infectious agent into the practice that other visiting dogs could catch, then they can see her in the parking lot or offer a home visit. That way we can get her checked for the above, rule out any other worries (ie heartworm, lungworm, heart disease, bronchitis, etc), and get her onto treatment to clear this quickly.
Any delay in having her seen and I would note that you can at least try to soothe her throat with plain over the counter glycerin/honey cough syrup (with no drugs in it) or even plain honey. Both can be very soothing to the irritated and tickly throat. Typically we will give a 1-2 milliliter (~1/4-1/2 teaspoon) as needed. Alternatively, you can try Robitussin DM with her. I would just say to make sure to use this preparation and avoid any similar syrups that may contain other medications like Paracetamol, Acetaminophen, Pseudoephedrine, Phenylephrine or caffeine (since these can be toxic). If it also contains Guaifenesin that is okay. Dose-wise, we tend to give this as 1/2 (half) teaspoon per 10lbs of the dog's body weight every 8-12 hours. Again, this can reduce the irritation that is triggering her coughing fits until her vet can have a check.
Overall, your lass’s signs and history are most suspicious of a bacterial or viral upper respiratory infection but tracheal issues are also a concern with these signs. And if this has been ongoing for 3 days already, then we'd want to soothe her throat with one of the above options +/- offer soft foods (to avoid any more throat irritation) until her vet can see to her and get her onto treatment to nip this in the bud.
All the best,