He used to feed 20 mins one side, now does 10 mins approx each side.
I'm a bit concerned about this statement. Surely he should still be doing the usual 20 minute feed and then doing some additional time on the second breast? Are you taking him off number 1 in order to move to number 2?
It's really important you don't shorten his time at the first breast. He should still be going just as long in order to reach the hindmilk.
It's certainly possible if he's gone from 20 on one side to 10 + 10 that he is now getting two loads of foremilk (he probably will be getting some hindmilk as it's a gradual transition but not all of it).
Sometimes excess wind/gas and greenish poos are also indicators of too much foremilk. As it's lighter than hindmilk it does often come back up more easily.
I would suggest you focus on that first breast feed. Make sure he is going as long as he was before. Put him back on it if he just bobs off but when he comes off 'satisfied' or 'finished' then offer the second breast. Then next time the second breast gets the 'full' treatment.
If you've been doing a few day of 10 + 10 then you may find your breasts have altered their supply a little so make sure you really focus on getting that first breast drained (you should sense his swallowing slow down when the thicker hindmilk is there) and in a couple of days you should be fine.
Don't forget you can also phone a breastfeeding helpline if you'd like to chat with an expert.
