I was put on antibiotics last night for a UTI and I have had brown discharge for the last few days. Is this due to the UTI? should I be concerned?

We also thought we were 8 weeks 5 days from my LMP, but the ultrasound suggested 5 weeks 6 days and we saw the heartbeat but she wasn't 100% on the date. The hcg levels were 3800 on may 24th and they were 6000 last night. Did this all sound normal? I'm a bit of a worry wart haha