I fell pg with #4 whilst BF #3( 12mths when I fell pg) AND I was on the mini pill, I thought I was safe LOL, I still managed to BF #3, have just weaned her in prep for #4 I was lucky, didn't loose my milk,but had to feed more frequently for a few days to up the supply again. I had a gf whom fell pg when #1 was 5 mths, so yeah it can definitly be done !
Oh and YOU chose how close you have your kids, don't let anyone have a say!!!