@TiaG, I cannot even imagine how difficult it must be to deal with the upheavals you are confronting. The baby, of course, is the hardest—but everything else, each one, would be enough to make things a lot harder. And, with Samson, given his age, you have the hardest D burden of all, a very young child.
We only have two children. Last Spring, my college son broke his foot, at school (3,000 miles from home), right before finals. He was scheduled to go on an internship that summer that would require daily driving. My wife flew off to CA for 10 days to help him out. Then I flew to Austin to help him move in, figured out with him how to deal with his internship, and worked multiple hours a day with him for the rest of summer. In both cases, one of us was largely unavailable to my T1D son. He was not so brittle last summer on Lantus, but there is no doubt that his control was somewhat impacted from the regular routines we have at home.
Harold was discussing earlier that he does all he can to share his time between his children, but that he spends 75% of his time on Liam. I have come to accept the fact that the proportion will hold true for us too. But I cannot renounce caring for my other boy when he needs help either. I think, in the end, the amount of time we spend on D care, however much it is, also needs to be in an equation with all the other tasks of our lives—the most important ones being our other children, but also everything else: moving, remodeling, work…
Both my wife and I have made career choices following my son’s D diagnosis that allow us to spend more time on D and on my son. But we have not curtailed ALL work, and ALL other tasks, and certainly not our other son, although we are ready to spend more time on my T1D son, because it is the nature of the beast.
As for your decision to breastfeed your newborn, my opinion has absolutely no importance, but, FYI, I support your analysis 100%. We did the same with both of our kids btw: they were breastfed for about 7 months each, even when my wife was traveling it lot. She would pump on the road, and we had a stash of frozen breastmilk that I would use when she was gone. That did not stop my second son from getting D of course. But I figure at worst it can’t harm, and at best it will significantly reinforce immunity to many possible sources of future health danger.
Unfortunately, I don’t have any tip to give you. We spend all of the time we can on our T1D son. When our other son needs us, we do whatever he needs, within reason, and our T1D’s care gets worse for a while. I feel guilty about it but my reason tells me this is the right thing to do.
The main issue, imho, is your psyche. You are doing the best you can in very challenging circumstances. Operationally, you cannot do any better. You have taken very rational decisions (of course, given who you are!). But you are permanently tired and recently gave birth, and Samson is facing daily challenges. Naturally, you feel depressed and guilty. Alleviating that is, I think, more important than other issues.
FYI, our recent events had led me to feel the same, btw—but I am aware that it is the wrong thing 
Would you like me to fly over for a week and help out to give you a little respite?
We all need sleep, so it’s understandable that everybody at your house is a little frazzled! I wish I could send you some sleep to enjoy.