Its about being mis-informed and having to blame something....that in this case being breastfeeding. People feel they need to give you a reason, a soltuion for baby waking/crying/farting/burping....when really, they're just being a baby !!!!
At nearly 10 months of age, and being my 4th child...i still get comments about DS waking thru the night 'maybe you should try formula'.....i now look at them in pity, because they really dont even know what they;'re talking about...how could they ??
You sound positive anyway...and good on you for reaching 4 months....