Welcome to Healthcare Magic forum.
The symptoms of nausea, dizziness
, pain in abdomen along with delayed periods most likely resembles pregnancy
but can also occur in delayed menses due to hormonal
imbalances or gynaecologic disorders.
You did the right thing by checking for pregnancy, however sometimes the test may not show positive if done improperly or with inappropriate sample.So you can repeat the test after a couple of days or better alternativeis to get a blood beta hcg
test or ultrasound
pelvis done to confirm the pregnancy.
Do consult your gynaecologist even if its negative to rule out other problems.
Wishing you good health.