I too wonder about my future in how long I will be able to survive with the pain, lack of mobility and having to take significant medications just to be able to not want to end things because the pain is too much.
I am enrolled in a Mindfulness course that is to help with chronic pain, which it really isn't doing anything to help with the pain but what it does teach is for you to live in the now rather than the past or future. This can help you not concentrate on the worry of how you might survive the future and focus on just making it through each moment as it passes. I'm not that good at that kind of focus but there are many in the course that are. You may want to think of enrolling in that kind of therapy or at a minimum, talk to your doctor about your thoughts and the help you think you need.