Well, first of all I'd advise you not to take in rescues if you can't stomach death. Taking in an animal that you know is in bad health is a risky business. I know you've spent a lot of time wanting a Nile monitor, but you can't base your whole life on an animal you only had for two days.
Take some time to grieve, take the body out of the freezer and find a nice place to bury it, and if being out in nature calms you down then go on some nature walks and reflect on where to go from here. Getting a new animal (one that's hopefully in better health) may help, but remember that death is a universal constant. Even if you have 5, 10, 15, or more years with an animal, most of them will have lifespans much shorter than yours. (Unless you get a tortoise, they will typically outlive you.)
Think about that and ask yourself if you can handle the death of a pet again, whether it comes quickly or a long time from now. If not, it may be best to hold off on getting another animal.