Welcome to HCM.
There are several reason of delayed or missed period.
First of all, have to exclude pregnancy
. You also got negative test.
The reasons are mainly PCOD or Ovarian cyst
associated with thyroid
prob, over wt, psychological upset, stress, hormonal
Therefore, you need to undergo some tests like thyroid profile and LH/FSH. Then consult with your doctor.
Do regular exercise to control body wt, avoid stress by doing deep breathing or pranayama in morning, avoid fatty food, need proper sleep.