hello. welcome to HCM.
Your urine pregnancy
test is negative even after one week of missed period, which means pregnancy is not the cause of missed period in your case. Depending on your age, there can be many causes, common ones of which are functional ovarian cysts, which need ultrasound
for diagnosis. All your symptoms can also be explained by hormonal
imbalance. Depending on result of USG, the gynecologist can prescribe hormonal therapy for onset of menses. You must get a USG and visit gyneac for appropriate treatment.