"It breaks my heart when I pick him up to burp him, and he just gets SO upset and frantic, and obviously looking to suck more. Sometimes he can be comforted by patting and shushing; other times not. I've been interpreting this as hunger, but perhaps he just needs to comfort nurse as you suggested?
Also, any idea how much an average woman could expect to be able to pump if it's been three hours since the last feeding? I think I remember reading 1.5 oz per hour, but is that per breast or in total? I just got out the pump for the first time in more than a month, and have pumped about 4 oz total. (This is the evening so I might have less milk for that reason.) Of course the pump is not as efficient as baby, but at least I can measure what's coming out!
Thanks to all for your advice and sympathy; I am so thankful for online communities like this!