I always try to think, this too shall pass. And it seems like the really tough things come together.
We are alone in a European country with no familial support. 2 DC, both ADHD and medicated, one with ADS, going blind and is currently nearly weekly in hospital on oxygen and IV drugs with a currently exacerbated chronic lung disease. Both are also going through intense exams to determine what school and uni they will go to in the next few months. We also bought a really old, crappy house that we are doing up. Plus, work and navigating everything in a foreign culture and language. This sounds like a lot but we are managing and are dealing with it OK.
So, my DH and I buckle down when everything happens at once, make a short-list of what absolutely needs to be done, and go from there. We take a nightly walk after kids are asleep and talk about everything and nothing. We make time for exercise. We get it when we break-down, have a whinge or a bad day/s, give each other space, and then we get on with it. DH has emergency leave and general leave that he can take when needed. We also let stuff go that doesn't need our immediate attention (fixing stuff, deep cleaning and so on).
We have also learnt that we need to work together, because no-one else and will fight for us and our children except us (learnt after DC suffered child SA at a kindergarten).
This is tough, OP. Allow yourself time to grieve and get angry, and then gather yourself up and make a plan with your DH. You can do this.