I can understand your concern. 10 days after your missed period if the urine pregnancy
test says negative then in all possiblity you are not pregnant no matter what the symptoms especially when you did the test 3 times. There may be some other reason for your delayed period and you may need to visit a Gynaecologist who can examine you and suggest some blood tests like LH/FSH/ Thyroid
profile/S. Prolactin/FBS/ PPBS/CBC and if needed an ultrasound
to know if there is any problem down there. Do not worry as usually this can be caused by something called PCOD
which can be easily managed with some lifestyle changes. Stress
itself caused delay in periods many a times. So relax and visit your doctor.
Hope this helps.