Emotional

I am feeling super emotional tonight! My period will be 4 days late tomorrow and that is not normal for me at all. Ever since I first started my period it has always been on time. The day AF was due I took 2 tests and both were negative. However they were under a lot of heat and a long car ride (20+hours) could the heat have affected them or am I crazy? Could I be pregnant and just tested too early? I am an emotional mess tonight! I'm trying to wait it out but I just want an answer. Anyone been through this or have any advice?