Possibility of pregnancy while having a light bleeding

Patient: Hi .. i would like to know if is it possible to get pregnant while you’re having a light bleeding?but im not hoping to get pregnant again besides my baby is too liitle for be an older sister i really want to enjoy her first .. i just want to know if its possible because lately we contact without using birth control .. but im having a light bleeding i think it was almost a month .. its started when im using injectables.. until now i bleed light.. we have contact last time early in the morning .. is it possible? i hope its not…. im not really good at writing english i hope you can understand