Thanks for the query.
Delay in periods can occur due to many causes like :
imbalance as in poly cystic ovary disease, stress and strain, weight changes etc.
- Thyroid hormonal abnormalities
- General conditions like anemia, nutritional deficiencies, prolactin
level of etc.
And usually 21 to 35 days cycles can be taken as normal only.
So possibly you may get your periods soon.
The spotting may be indicating onset of periods.
If you had unprotected intercourse
around the time of ovulation, there is possibility of pregnancy
Sometimes urine pregnancy test kit may not detect early pregnancy.
So if you want to rule out the possibility of pregnancy, better to go for blood test
for pregnancy once.