Unless both of you had clothing that was soaking wet with thick secretions that were amenable to sperm survival and a sperm swam through them (sperm can't be exposed to air or it dies) this is not possible.
Lolita, sperm do not pass through clothing. The sexual excitement may have upset your hormones, and the PCOS could be a reason for no period in spite of the meprate. I don't see any possibility of pregnancy, and you are not listing any other early pregnancy signs. Run a home test if you want to ease your mind. Good luck!