BIG HUGS
You are a very loving and caring owner. Round the clock care for the longer term is very exhausting - not just physically but also mentally.
I agree that Chase is still exhibiting too much zest for life and normal species behaviour to warrant euthanasia at this particular moment and that I would feel conflicted as much as you were I in your shoes (I have been in similar situations though). You are however coming very close to the area where is no right or wrong as to whether euthanising sooner or later; it is just a matter of how you approach the issue and which factors weigh heavier for beyond your personal convenience or fears of loss.
The fear that Chase may pass away while you are not there is also another major factor that is in play because you are feeling very guilty already for having to leave him when your special baby is so fragile and hanging in the balance.
It's not the kind of conflicted or highly charged scenario that anybody of us would want having to deal with because there is no clear and easy path. Whichever way out you choose will come with an emotional price because you have to sacrifice something important for the benefit of an other aspect. All you can do is follow your heart - having done the best you can and having styed true to your heart is the rock to which you can cling to whatever happens; because that is the one thing you as the owner has control over but most of the rest is out of your control and you have to deal with it as it comes at you. And in that way you have a foundation that you have not betrayed Chase in the most important way for yourself.