Welcome to SailNet. I am sorry to hear about the loss of your mast. I have a couple thoughts here:
Like other's have said, I would suggest that you talk with your insurance company. They may total the boat for the price of a mast, but they may not. Depending on the company, it can really simplify life if they handle it.
Next option would be to buy a spar section. Catalina had it's own proprietary spars for some boats and some spars. Most of those original Catalina spars are no longer available. But many of the Catalina masts were standard sections made by the usual extruders (Maybe Dwyer, Kenyon, or one of those) and those standard sections may still be available. The cheapest thing may be to buy a new spar section from the manufacturer and then transfer the old hardware and rigging. That would require contacting customer support at Catalina and asking them to provide you with the manufacturer and spar section that was used on your particular boat. A spar section for a boat that size may be something in the $500-700 range.
It may be possible to sleeve the mast, but that would still require locating a short section of the correct spar and it probably won't save much since its expensive to do that right.
Find a used spar or rig. That may be possible since many of these boats have been been lost over time to one screwball thing or another. The other thing might be to buy a really beat up Catalina 22 and strip it. I know of a number of cases where that was done with Catalina 27's and Alberg 30's. It is not unusual to find really beat up examples of the Cat 22 for free or for a grand or two around here. (Here's one for $200 https://annapolis.craigslist.org/boa/5766726188.html
, which is a pretty cheap price for a mast, but of course then you need to dispose of the boat).
Whatever you do, good luck in getting the old girl back together and out on the water.