I have a 12 wk old DS who is ebf. She never went more than 2.5 hrs between feeds and often cried after feeds. Milk supply was never a problem in fact i had too much and sprayed milk everywhere and leaked heavily. With all the (comfort) feeding she put on 2lbs in the 1st 4 weeks.
From the beginning she has been very windy, mostly from her bum, and LOTS of dirty nappies, I'd be lucky to have 1 nappy a day that was just wet and not also streaked with poo. So that's 5 or 6 bowel movements a day. Most of these would be very explosive or "bubbling" out! Very often she'd have a bowel movement during a feed or straight after. Her poo was completely liquid with no solid parts, all to be seen was the stain on her nappy usually yellow heading for green in colour.
Having done some research I put it down to 1 of 3 things -lactose intolerance, allergy to cow's milk proteins in my diet or foremilk hindmilk imbalance. As the 3rd was easiest to check for, I began to keep her on each breast for much longer than I had been. I only go to the second breast for maybe 2 feeds a day the rest of the time she just has a long feed at one, but this requires perseverance but I'm hoping she will get more patient! She protests as obviously she had gotten used to the easy foremilk and now has to work harder for the hindmilk, but it has worked a treat.
As I said to my DH she's like a different baby now - much calmer & happier, sleeping better and only pooing once a day now. I thought it would be helpful to other mums to share this as i find you get fobbed off by healthcare professionals who say any sort of poo & any frequency of poos are all perfectly normal in bf babies (This is my third ebf dc so you'd think I'd know it all!!) but I knew she wasn't happy and her poos weren't right! Having read up some more on foremilk hindmilk imbalance I realise how common a problem this can be (up to 2/3's of ebf babies suffer this at some stage) and how easy it is to slip into. In retrospect DS2 probably suffered from this too as I remember talking to my GP about his very frequent liquid poos too but got the usual "all is normal in the world of ebf nappies".
I think it's really worthwhile looking into the whole foremilk hindmilk imbalance if you have a baby who cries & feeds frequently, but to me the big giveaway were the explosive poos & wind.