Is there an over-the-counter medication available in pharmacies to treat bacterial vaginosis?

You do seem to have the symptoms of bacterial vaginosis (odour + heavy discharge...usually the odour is a bit fishy and the discharge is coloured, more grey than white). It is certain that in order to have an official diagnosis and to eliminate other possible causes (STI for example) it is preferable to see a doctor. However, in answer to your question, there are indeed treatments for bacterial vaginosis. The only treatment that does not require a medical prescription and that is recognized to be effective even if it is not antibiotic is Prevegyne (intravaginal vitamin C treatment for 6 days). costs around 35$ and you will have to ask the pharmacist who will also confirm your symptoms. Other treatments are based on antibiotics (intra vaginal or by mouth) and you need a medical prescription to get them.