Missed period from stress

Hey guys... I have been extremely stressed. Honestly I’m not sure how I’ve been holding it all together 😔😪 My period was scheduled to start on September 4 and today (September 19) I still have no period. I have taken 5 pregnancy tests and they all have been negative. Now I’ve been noticing some breast tenderness and soreness in the mornings and at night. I’m thinking it may be the beginning of PMS which usually starts the week before my period. My question to you all is has your period ever been delayed by stress? If so, what’s the longest you’ve gone without a period? Did anyone think it was stress related and was actually pregnant? Help!