Peed before precum mid cycle period now two days late lots o

alright so me and my girlfriend were fooling around. i didn't take a condom that time and she was sucking for a little and then i went inside her but didn't come. also keep in mind that i took a huge piss right before this all started. i didn't even feel close to cumming it was about ten seconds i was inside her. this was five days before her ovulation was supposed to start. she had a state test and we got into a big fight basically the week after we did this and that's around the time she should have had ovulation so there was lots of stress and then we forgot Februrary was shorter month so we started stressing early about he period i'd love to get some help just to relax and get my girlfriend to relax because i know it can delay it a lot. i'm sixteen and she's seventeen. her last period was February fourteenth and ended the eighteenth we then had this sexual encounter on the twenty seventh. she has a thirty one day cycle and was supposed to get it the seventeeth of this month and now it's the nineteenth and nothing yet. she hasn't had any pregnancy symtoms but her boobies haven't hurt either which they usually do before her period. any advice would be great. oh and the week and a half we broke up was the day we had this sexual encounter which is February twenty seventh to basically around march seventh and we had this big state test that caused a lot of stress march first second and third anddddd her diet has changed in the past month dramatically as to changing times she eating and she has also had a change in physical exertion. so all in all should i be worried? or is it just caused by stress and her change and diets and her worrying like crazy about it now?