someone give us a hand

so last week me and my boyfriend has sex for the first time and we had sex 4 times thoughout that week on different days and we used condoms each time but I haven't got my period yet and according to my period app I should have started last Thursday. in the past my periods have been quite irregular either a few days up to a week early/ late. I've been quite panicky about it and not sure what to think.