I would take her to her physician as soon as you are able, it is certainly not healthy for her to keep coughing
. The coughing
will hurt her insides if it is too strong and vomiting will prevent her from getting her much needed nutrients from food, etc.
I really am not able to tell you what it is, it could be a number of things, and, as I said, it would be best if she saw a doctor.
Please let me know the outcome, I know she must be miserable.