Your boss is ok with your performance. Why overthink it?
Imposter syndrome happens to everyone. You interviewed, you got the job, you are not an imposter.
But ask for help when you need it and it can take a long time to learn about the systems. Your boss should be able to point you in the right direction. But do your homework! Is there good documentation to read to help get up to speed?
Also you might try writing down your day to day feelings in a journal etc..
Imposter syndrome happens to everyone. You interviewed, you got the job, you are not an imposter.
But ask for help when you need it and it can take a long time to learn about the systems. Your boss should be able to point you in the right direction. But do your homework! Is there good documentation to read to help get up to speed?
Also you might try writing down your day to day feelings in a journal etc..