Hi Trenchman
I had my SCT back in 2017 and I remember feeling exactly the same, I believe it is entirely normal, first of all on a physical level the drugs really take everything out of you and it can take anything up to 2 years before you start feeling “normal” again, even now I am at the point on a really tired day of thinking “is this still the SCT or am I just really tired today” so it goes on for ages.
On the mental side, the fight against the cancer takes all of your energy and focus, once you have finished with the SCT you no longer have this focus and that can leave you feeling lost and clueless. It does get better it just takes some time, see if you can find something else that you enjoy that you can focus on.
Best of luck to you
Paul