Thank you for your query.
Merely finding of decidua in the sample is not indicative of a pregnancy
Chorionic villi or fetal tissue should be seen in the sample to prove a pregnancy.
rarely in cases of complete abortion
or ectopic pregnancy, only decidual tissue might be seen.
A urine test is only 97 % reliable, and could be faintly positive even in case of an ectopic pregnancy which spontaneously resolved.
I think you should consult a gynecologist, if you are desirous of further issues, and definitely for your delayed periods.