It is very stressful, which sucks, but hopefully your concern will turn out to be misplaced. The uncertainty does take a toll.
In a worst-worst case scenario, there will be something you can qualify for. At a minimum there will be the generic welfare program run by your province under whatever name they are using now. There will also be an enhanced provincial welfare program for disabled people that will pay a bit more.
Second worst case, you can apply for CPPD. Unfortunately they are very, very slow in reviewing applications, so if your insurer does say that you won’t qualify, then I would encourage you to look into your provincial programs right away. Some provinces have programs that will help you with bridging the time period while you wait to get approved. Usually though if you qualify for CPPD you will also qualify for LTD. CPPD can help you survive while you appeal your insurer’s decision.
In the best case scenario, your insurer will agree that you are disabled under the new definition of disability. Mine did. We hear a lot about the horror stories and not much about the cases that just proceed normally. It is hard to not let your mind run wild with what-ifs when the personal consequences are so severe. Note that the any-occupation concept is not literally any occupation - I don’t know the full details, but there are some limitations about the type and nature and pay of work that is suitable for you. My policy said that I was Totally Disabled unless I made a certain percentage of my pre-disability base pay. I understand from the lawyer who runs this site that a concept like that applies even if your policy is not explicit.
You will probably need to apply for CPPD either way. Under most LTD policies the insurer can deduct the amount of your CPPD from the amount that they pay you so you will probably be expected to apply for it if they do agree that you still qualify as disabled under the new definition.
So I guess my main advice is to try to just let things play out, do a bit of research on the alternative programs that might be available to you so you can act quickly if you need them, and hope for the best.