@iamsuchatit
Wow, nosey bints they are. Probably only 'making conversation' but that is the usual spiel when someone is being rude 'I was only asking,' I was only joking,' and 'I was only making conversation.' 
If it bothers you a lot (and that is understandable,) just say 'yeah' when they say 'are you breastfeeding?' Then change the subject. Can't think of what to say to your mom though!
I don't what's wrong with folk, and why they have to be so rude to other people. My daughter's friend who is 22, got married in 2017 at the age of 20 (to the lad she has been with since they were fourteen!) and she has just announced she is pregnant.
The amount of nasty, snarky comments she has got since announcing her pregnancy is disgusting. You'd think they were both blimmn' twelve! 
I mean, even FAMILY members of hers are wittering on about how young she is, and how she has got her whole life ahead of her so why get knocked up now (urgh rude!), and how she is 'tying herself down so young.'
When I said 'congratulations Lily, how lovely to hear you and Tom are having a baby!' and gave her a hug, she burst into tears. I was taken aback and thought it was the baby hormones, but it wasn't; she said I am one of the very few people who have been nice about her being pregnant, and she has had hate and nasty comments from everywhere since she announced it a month back.
Weirdly, her husband - Tom - has not been in receipt of the same vitriol and nasty comments. In fact, most of his mates have said 'well done mate!'
People just need to fuck off .... really.
Oh, and congratulations on your new baby! 
disclaimer Lily and Tom are not their real names.