Welcome to HCM.Pregnancy
test should be done 1 wk after missed period to get positive result. Early tests are insignificant.
Do a fresh USG lower abdomen to detect product of conception or other underlying pathology.
If pregnancy test is negative,then do some hormone study and urine examination for infection.
Your features may be associated with Pre menstrual syndrome. Then need some medication.
So consult with your gynecologist and take advice according to your test reports.
Take healthy diet,avoid stress
,do light exercise,avoid extra salt & coffee and proper sleep.