I just had to put this out into the world so that I can hopefully remember this long into the future:
Ask for help.
Today I finally called the lactation consultant again, something I've been considering doing for the last two weeks. Nursing W has been iffy from the start. There have been moments that felt totally natural and right, but there have been plenty of moments that felt frustrating and wrong. More than a few times I have said "It's like he doesn't like the taste of my milk" as he fought latching on for the umpteenth time in a nursing session.
After talking to the consultant for 3 minutes, she had given me a name for what is likely the problem (overactive letdown - something that had been floating around in my head for a week or so, as I pondered possible problems) and gave me a couple of online resources to look into to see if they confirm her theory. So far they do.
If this solves the issues we've had it will be such a relief. I often don't like to ask for help - though I am usually happy to accept help when it is offered. I don't know why that is, but there are times when I need to get over myself and just find someone who a) knows more than I do, b) has more experience than I do, or c) is not caught up in the morass and has a bigger perspective than I do. This is one of those times.
On a related note: my doctor told me to tell my husband to call her if I seem depressed. I should have told him to tell me to call my therapist. (I've been having the anxiety again lately). But that goes for friends, too: if it seems like I need help, remind me I said to ask for it.