Excessive sweating uncontrollable crying missed cycle was suppose to start june 29th but no show, throwing up, backaches lower stomach cramps "could I be pregnant? ".Eventhough my home pregnancy test came back negatives

Possibly. More likely you have a delayed cycle most likely secondary to stress and some cramps secondary to functional ovarian cysts. If your pregnancy test remains negative and no period comes, consider an evaluation, ruling out thyroid disease and consider an ultrasound.