Ouch!!!
At about 12 weeks (during growth spurt) DS got into bad habit of feeding twice a night again - big feeds, off both sides and not taking much during day.
Over week 13 I gradually pushed back his night feeds so we were back to one feed, and I'd only give him part of my left boob for that feed.
Over week 14 DS suddenly started going till 5:30am (10hrs) every night, and again I was still only giving him part of that left boob
Then over week 15 and 16 he began to go the whole night, consistently, not needing a feed till 7am (11.5-12hrs). Has been for 6 consecutive nights
He is 17 weeks tomorrow. The problem is that my left boob STILL hasn't adjusted to this, and since the start of 14 weeks when he was going till 5:30am, my left boob was/is very engorged by the time he fed then. Every night for the past 12 nights I wake around 4:30am when it's starting to get full and uncomfortable and (not wanting to pump and keep the demand up) I dont' get much sleep because of it until DS feeds at 7am. I'm sure I've only taken a few days to settle down before, so why is it taking weeks now!!!?

By morning it's rock hard and very uncomfortable - I can't wait to get DS on for his breakfast!! I don't think it's even starting to ease at all - last night I gave in and pumped a little off (at about 4:30) so that I could get a bit of sleep - painkillers don't seem to work.
I pump both breasts at around 8:30-9:30pm, not completely empty, so that I can feed this at bedtime the following day (it's his bottle practice each day). I can't see that this is causing the problem though cos it doesn't have the same effect on my right boob, which feels fullish but not bursting by morning. The left has generally been more prone to engorgement since the start but has never taken this long to settle down again.
Has anyone got any suggestions on what I can do to reduce engorgement overnight?? After LO's morning feed I have no engorgement for the rest of the day.