Really sorry and sad to hear about your lovely boys Amethyst_ice it can`t have been easy. If I`m totally honest, I went through a lot of grief and stress when I kept rats. I had three rats originally. One single male and then two brothers, all came from the SSPCA. I then took on three adopted rats who I later decided (very reluctantly) to rehome as I found keeping them too much. They were wonderful pets, but oh so difficult to keep well and healthy. I lost Winston my first old boy to old age and hind leg paralysis. I took his demise so hard I couldn`t eat for a week afterwards. My two brothers, one died from urolithiasis, the other heart problems.
It was agonising.
I decided not to keep rats after that and went on to keep rescue fancy mice for ten years or so and then moved to hamsters, which I now keep only one dwarfie.
I would say rest well, remember the good times and give yourself plenty of time. But rats can be a labour of love. Hamsters are far more easy to keep in my opinion. x