Pregnant?

So my period was supposed to come last few days and it’s still not here. Me and my boyfriend had sex on the 19 of June. I have a hard time breathing even walking a short distance. I felt nauseous around raw food at work cause I work at McDonald and the smell of raw food never bothered me but it has recently. I use this app to help watch for my period but it’s Been four days since I had it and I’m a little worried that I could be pregnant or something else is wrong?. I know someone of you are going to be Judge me for it, I just want some advice and maybe some ideas on what to do ?.