I don't know if you happen to be a "pray-er," but when I'm stressed, the first thing I do is pray. It calms me down immensely, and I just give my stress to God. It seems to clear my head and give me direction, too.
I try to remind myself "this too, shall pass," and yes, eventually, it does.
Also, it helps to do something active. For me at least, it helps to sort of 'burn' the stress out, as I keep busy and as active as possible, outside, if possible. Even a good, long walk can be helpful. When I'm stressed, I just try to keep moving.
And, dealing with one issue at a time, I think, is key. We can only do so much, and sometimes just sitting down and writing out a plan, step by step, can really help the situation.
I'm so sorry you're dealing with so much right now. It has to be so tough for you. I don't know why, but it always seems 'when it rains, it pours' when it comes to stressful situations. We hear you and are here for you!
I hope things are better soon, all around. Best wishes and prayers.