Thanks for the query.
Delay in periods can occur due to many causes. Like:
imbalance due to stress and strain, weight changes, poly cystic ovary disease etc.
- Thyroid hormonal abnormalities.
- General conditions like anemia, diabetes
. Sometimes urine pregnancy test kit may not detect early pregnancy.
So, better to go for blood test
For more details : http://srsree.blogspot.com/2012/05/pregnancy-tests.html
If test comes negative, there is less possibility for pregnancy.
And the symptoms you are having could be part of premenstrual syndrome
You may get your periods soon.
If you do not get periods even after one week, consult gynecologist once and take tablets to induce withdrawal bleeding.