Antibiotics or Pregnancy?

So I had recently gotten a UTI so I started taking the antibiotic nitrofurantoin to treat it. I’m on the last day of taking it and my period is 2 days late. I typically expect my period to be late, but it’s starting to get me worried because I’ve recently become sexually active and I’m a big worrier. Is it true that antibiotics can delay your period?

Follow up question: last week at the doctor’s I gave them a pee sample to test if I had a UTI. From that sample, could they have easily determined if I was pregnant? The last time I was sexually active was 2 days prior to that.