Hi all, i have a beautiful 11 week old baby and im only feeding he has a pacifier?

i bleed for about 35 days then after about 7 days i bleed ain for 5 (not sure if this was my period. now at the moment ive started to have a bit nausa although this could be due to lack of sleep. my first question is could i be pregnant again even though im feeding and my baby is under 6 months old (ive been told feeding is a form of contriception) and my next question is could the bleeding i had for 5 days be my period. thanks