Agreeing with the advice and info you have received so far. D3 and oxygen are where you want to be.
In the meantime, if you have any old Imitrex, it will probably still work, even from three years ago. But you ought to be splitting doses. See this file: https://clusterbusters.org/forums/topic/2446-extending-imitrex/ Once you get O2 set up, you will be using a lot less triptan.
There are some things that work for some people when they don't have standard abortives. If you look in this file -- https://clusterbusters.org/forums/topic/6213-basic-non-busting-information/ -- under "Treatments without O2" (down toward the end), there a bunch of things to try, including energy drinks/shots (often works), voluntary "brain freeze," standing in superhot water (this seems to help a lot of people), and inhaling cold air from a home or car air conditioner. You might also try starting on some Benadryl (4 tablets/day, or what you can handle and still function), because allergies have been shown to have a big effect on CH. Also in that file, there's a long discussion of oxygen and maybe some other things you'd want to know.
Busting is also something you want to have as an option. There's a summary of busting principles at the end of that file.