I’m scared! 😩 HELP!

So my last period started on Feb 4th. I started getting a UTi yesterday and got on antibiotics today is my second day of taking them. I’ve had a little discomfort on my lower abdomen since last night. Earlier got in the shower and had some spotting on my underwear. I just went to the restroom and cleaned my self and got this brown discharge. What’s going on? I’ve never had this happened before. 😩 Also I don’t have any symptoms of my period, usually I get lower back pains.