Please help

Hi girls.  So I went to the hospital on Friday because I thought I had a Urinary infection. It was burning, itche, and I was getting some white flu out.  So when I went to the hospital because it was bad and I was that way for almost a week.  They gave me this injection, and they gave me 4 pills to drink.  They gave me two prescription one for one pill and the other one for 4. I had to take them all at once, just one time.  I did everything they told me to.  The next day after taking the pill which it was yesterday I started bleeding.  I don't suppose to get my period until next week. It not like a heavy period bleeding but I am bleeding and I have to us my pads.  I am worry. It is normal for that to happen after taking those pills for urinary infection? How do I know if it's my period? Maybe I got it earlier?  I usually get pain and pimples but nothing so that's why I'm not sure.  Please help thank you girls