6days postpartum & in a lot of pain

I'm 6 days postpartum & I'm experiencing a lot of pain when I urinate. I had a 2nd degree  tear but I don't think that is the cause. I went to the doctor & was told I had a bladder infection and was prescribed antibiotics and it isn't working. It stings and hurts so bad I cry while trying to go & im unable to empty my bladder. Any other mommies experience this ? Please help!