I had a period in which everything seemed to be going wrong, from job changes with massive paycuts to miscarriages to unwanted interstate moves. In retrospect, I should have gone to a therapist, so that's my advice #1. You are dealing with a big change, and it is ok to talk to someone who is skilled in helping people adjust to big changes. If you have an EAP at work, you may even be able to access this free or at very low cost. And take the time to do whatever it is that brings you joy or relief -- long walks, hugging kids, hobby, whatever your magic button is. Your body and brain can't handle all the stress all the time.
The mental shift that helped me get through it was when I woke up one morning and, instead of asking "why me?" I suddenly thought, well, why *not* me? Yes, the issues I was dealing with sucked, but at least I had resources to deal with them -- we had two jobs, we had supportive families, we had access to good medical care, we had savings to get through the financial tight spots and pay for the medical treatments, etc. I thought of all of the other families who dealt with that sort of thing without my resources, and, boy, did that give me a new perspective. The problem is that you can't force that; it took me probably a month of being so rage-filled that I literally could not find words for my feelings, and then suddenly I woke up one morning and it was like the dam broke, and I could talk and reason and get a little perspective back.
You are dealing with a loss -- maybe not the loss of an identifiable thing or person, but the loss of a dream of what your life was going to be like (which, frankly, is what we all grieve even when we do lose a specific thing or person). It is ok to grieve that loss. And that means accepting that things are going to feel sucky for a while, and giving yourself permission to feel sad about it while you adjust. But you have the resources (internal and external) to get through this, and you will get through to the other side. Just keep putting one foot in front of the other, and make an effort to think about the good things you still have, even if it feels forced for now. Because one day, it won't feel quite so fake any more.