Ay Tia, possible talaga kasi nag-expire na ang injectable mo before kayo nag-Do, so there's a chance na. Eight months pa lang ang bunso mo, alam mo ang struggle ng back-to-back pregnancies kaya I get why you're worried. The best thing is to take a pregnancy test na or check with your OB agad para sure, lalo na kung nag-miss ka na ng period or may weird symptoms ka. Hugs, hope everything's okay with you!