Scared.

Okay so me and my boyfriend haven't had sexual inter course in a whole 4 weeks until last week, we had sex, I was reminded by eve that my period was supposed to come on this week but it hasn't. I'm on birth control (the patch), I've even took a pregnancy test and it came out negative. 🤦🏽‍♀️ My periods are usually on time. However, like any other worried teenager I went to Google. One of the reasons for late periods were exercising. I've started exercising a lot lately since last month, because of band camp. I was thinking that could be the reason, however I am 4 days late and I'm still scared. What should I do? 😔