Suggest Remedy For Painful Urination

While on my period, I felt like it was hard to pee, however could pee fine. Right after my period was finished I started to feel stinging when I would pee and thought I had a yeast infection. After using the over the counter meds, it did not go away. I notice I starting getting blisters or sores. Now I'm having throbbing pain and it almost hurts to sit or sometimes walk. What could this be?