Stress and missed period

So my period is 5 days late. I’ve taken tests and all of them say negative. Not even a hint of a small line for pregnancy to be seen. I’ve been working two jobs every day, 16-18 hours a day. I’m stressed out all the time especially lately due to work and my relationship. I haven’t been sleeping, my eating habits are off and on of not eating at all and eating too much. I’m tired and I’m hoping I’m not pregnant. I know stress can cause missed or delayed periods, thoughts?