Close I know that feeling really well. For me it's particularly hard around established families with multiple siblings, all in a lovely close-knit clump (probably because I'm lucky not to have too many pregnancies or baby bombing happening at present). I have found my kneejerk bitterness getting triggered often by my sister and two SILs, who have three kids apiece. Not long ago I almost broke down when my SIL was innocently showing me a slideshow of the kids at various ages - bathing together, birthday parties, etc.
I think for me the anger comes when people are just so thoughtless and oblivious about how lucky they are. The bitterness just builds up - until it feels like even the most incidental comment or action (or inaction) is a kind of cruelty. A lot of the time, I know it's irrational, but that doesn't really help. I had a big emotional meltdown with my mum a few weeks ago, because I felt that she was just turning a blind eye to this massive trauma we were facing on a daily basis. In truth, she's probably just been wary about saying the wrong thing.
We're at a bit of a different stage, in that we're still starting IVF - so I can only project myself into your feeling. But, I thought I'd mention what has helped for me recently. I think it's a little to do with what Place said upthread. A lot of my grief has been to do with my sense of how this affects my DD, but then - I just got a flash a few days ago of the other side of the coin: she has been so lucky to have this intense, creative relationship with both of her parents. We may not have the ideal perception of a nuclear family, but there are wonderful, special things that happen because it's just us three. Also - all those other families are great and all, but they're not ours. Maybe our family will always be a little idiosyncratic and off-kilter, but that's okay. This has given me a modicum of peace.
Also, I'm not at all religious, but I think I've been casting around for books that address spiritual struggle in some fashion. I'm still looking for something that resonates properly (I read Help by Anne Lamott, which had moments of resonance, though also felt a bit hokey) - but somehow the act of putting this experience into the category of general suffering - rather than this lonely ghetto of infertility suffering - sort of gave it a context and a dignity, if that makes any kind of sense.
The other thing that has been helping me is kind of boring: running. I am a complete non-runner. But, I've been really down and even thinking about SSRIs. Out of desperation, I've been trying to force myself to go. It's only been a week or so, but oh my god, all discomfort is worth it for the endorphins. They basically make me feel for a while like my body is a good place to be. Which is a big change. Also, it helps relax me, which is not a small achievement.
Oh, the other thing - sorry this is majorly long, btw - is NOT reading on my commute. This is totally random, but usually I tune out by reading social media or news on my phone. I forgot my phone one day, and was just forced to look at people, and at my surroundings. For some reason (not always, but cumulatively) this has been helping to keep things in perspective. It's interesting to think about people's stories, speculate about their own struggles, etc.
Also - I really like your analogy about your DM and the money situation. I can relate to this, because when I'm in that mental space you describe, this is just how I feel. LIke, I know it's wrong and imbalanced, but I still can't get myself out of it. But, also just wanted to say - maybe it's okay to feel this way at certain times or for certain periods. At least you know that's not how you want to feel.
Argh, this has turned into a true epic. Sorry - i touch type so I always end up writing too much. Anyway, just some things that have helped me. No guarantee I'll be feeling so resolute next week, tho. Sending thoughts. Hope you've been able to get some sleep.