I also am tone to utis but I always just up my water intake and add lots if cranberry juice. That always works for me. I'd be concerned about a medication that can be toxic. Dosages are based on your size not necessarily the time span you were on it.
For now I'd recommend lots of water to keep you hydrated. Then look and see if you can't find a cough medicine that will cover the rest of your symptoms. If it lasts too much longer you should definitely get in with your mom to see a dr.
Nail patella syndrome, osteoarthritis, complex migraines, eosinophilic esophagitis, major depressive disorder, OCD, and fibromyalgia, IBS
Meds: flovent 220 mcg, flexeril 10 mg, zonisanide 100 mg, omeprazole 40 mg, Cymbalta 60 mg,dicyclomine 20 mg, elavil, 10 mg, Xanax prn, hydrocodone prn.