Just want to say, Meg, I've felt the way you seem to be feeling, and it's awful.
No treatment seems to work, it's easy for everyone else, you begin to wonder more and more whether this thing you're wrecking your life for really is all it's cracked up to be... you look at your own family of origin and your relationship and acknowledge the bits of it that are difficult, and think 'how is this going to be better with no sleep and less money and tantrums?' You look at your friends with kids and their lives inspire a mixture of envy and extreme boredom. And then at the same time you're left with a feeling of failure and alienation, and all the world constantly reminds you that you're missing out on the most precious experience there is, and the thing that makes you a woman.
Leaves you feeling quite flat - hard to think where the pleasure & joy in life has gone and whether it will ever come back. Or that's what it's been like for me, anyway.
I tried until I physically & emotionally couldn't do it anymore. I do feel better for having stopped. But it took a couple of false starts - stopping trying and then suddenly getting a resurgence of hope.
Let yourself feel despondent. I'd suggest trying to talk a bit to your partner about how you feel & see how he feels. It's a bizarrely hard thing to do but it made things so much better & clearer with my DH. 
and hang in there.