Hi and thanks for the query,
the commonest cause of delayed periods in a female of reproductive age is pregnancy
. adding to the fact that you had unprotected sex, its an additional major reason to suggest this could be a pregnancy. The signs and symptoms you are experiencing, being lazy, frequent urination
and looking bigger are generally called sympathetic signs of pregnancy. It is fundamental for you to do a pregnancy test. Its true other conditions could cause similar symptoms, but a possible pregnancy must be excluded first. It might be important to know that ejaculating outside is one of the most ineffective birth control methods. Other measures like condom use could be more appropriate. Discussing with your physician on other available and adapted methods could be of help too.
Thanks and best regards,