Thanks for the query.
The possible causes for your symptoms are :
imbalance leading to intermenstrual spotting.
. If you had unprotected intercourse
around the time of ovulation, there is possibility of pregnancy.
Urine pregnancy test kit may not detect early pregnancy sometimes.
To get accurate result better to test one week after the missed period.
As your cycles are irregular, better to go for blood test
for pregnancy to get accurate result.
If the test comes negative, the possibility of pregnancy is less.
You can consult gynecologist and take tablets to induce withdrawal bleeding.
Along with that you can use hormonal pills for few months to regularize the cycles.
You can continue treatment for PCOD