I think one can look at your question two ways.
1. When do we know what our future will look like? Can we handle our current job?

But then I think of your question in a completely different way

2. Is the life that I am currently living, the life that I want to live?

I am 8 months pcs and it has made me think long and hard about my careers, how I can modify/ change them. My relationships, some have grown stronger, some fallen apart. The way I pass my time is completely different.

Maybe this experience causes some to make some serious life changes. Hopefully some for the better. I have already lost a job that I miss dearly. That was one of the most difficult things for me. But hopefully something better is on the horizon.

4 months is very early for many of us on the slow boat to pcs recovery. It will give you lots of time to think.
Su Seb