Can you get pregnant while breastfeeding?

Hi ladies,
I am FTM due in September. I was always planning on at least trying to have my children close in age. I also always planned on breastfeeding. Lately a lot of ppl are telling me you can't get pregnant while breastfeeding. Is it true? I don't know what I'm going to do. It's very important to me to BF my child forat least   6mo-1year but I thought I could get pregnant during that time. Advice or thoughts?