Birth control and antibiotics

So I am on Blisovi fe 24 and I had to take antibiotics (azithromycin) for a sinus infection. I was a genius and didn’t read the info sheet till I was almost done with them. The sheet said that it may make hormonal birth control less effective. I didn’t realize this so we didn’t use any other type of protection. Should I be concerned? Should I get a plan b or do you think it’s ok?