12 week old crying while feeding

[roseanneamy]

My LO is 12 weeks on Friday, and has started crying hysterically at some feeds during the day, and especially the last feed of the day, when we put her to bed in her cot.
Before the feed, she is showing hunger cues (saying ahh, chewing her hand, rooting) and sometimes will eventually feed but sometimes refuses. For the last feed of the day, I'm having to feed her standing up - she tends to be fine then!

• she is exclusively breastfed
• fed on demand
• feeding between every hour - 3 hours.

Help! What's going on?!

OP, does baby start the feed and then start fussing?

It's a mix - when she is having a fussy feed, sometimes she doesn't latch on at all, sometimes she latches on for a minute or so then pulls off and cries.

Just a possibility: at 6 weeks old my son (also fed on demand and exclusively breastfed) started getting distressed during and after feeds. It turned out to be silent reflux, which can be a tricky thing to spot, because unlike 'normal' reflux baby doesn't necessarily bring anything up. The only (but bloody awful) symptom my son had was getting very upset around his feeds. We were able to treat it very successfully with medicine, which he needed until he was about 4 months old, by which point he'd grown out of the reflux. Maybe worth a Google to see if the symptoms ring any bells?