Thanks for the query.
As you had unprotected intercourse
around the time of ovulation there is some possibility of pregnancy
Though you are having some symptoms of pregnancy, just by symptoms we cannot confirm it.
And sometimes urine pregnancy test kits can give false positive results.
So you better go for blood test
for pregnancy. If the test comes negative the cause of your delayed periods could be some other like stress
and strain etc.
In that case you can go for tablets to induce withdrawal bleeding after consulting your doctor.