well I am 38 & have just been breastfeeding my Dd2 who is 6.5 mths in the Beefeater !
I've also feed DD1 on planes at ages 7, 11, 17, 19, 20, & 24 mths
I have felt self conscious, but a little voice says to me that I am doing my girls proud & I am also protecting myself against breast & ovarian cancer. I would hope their immune system is as strong as it could be, along with their teeth. Also why would I compromise their health to please someone else ?
My boobs don't leak at night ( I haven't excercised yet, but will be attempting a step class tomorrow am so will let you know !), in fact they don't leak at all - tip - put pressure on the nipple that you're not feeding on.
On the selfish side, I have no intention of giving up until I've lost all my baby weight (8st 7lb, 4 -6 lbs to go).
For the frowns, I would ask " are you OK? you look like you're in pain?" that should stop it.
You sound like your doing great - there are no end of reasons to contine - vist kellymom.com for a start.
My Dd1 ( now 3yrs 7 mths) is very healthy, never had sickness & diahorrea or vomiting. A couple of my friends said are you ever going to give up ? I just thought of their kiddies ailments, smiled & said I doubt it.
BTW I'm not a freak, although I am a bit tipsy !