I'm not sure what you are trying to convey, but if you are a nit-picking type then I'd go with bartonig's suggestion. But if you are in a job which requires that you be precise and accurate then I'd offer....
My job is very demanding.
I have a very demanding job.
Something like brain surgery or motherhood, for example.
I wouldn't expect to use demanding in relation to myself - it is the job, or the task that is demanding.
I set myself very high standards.
I set very high standards for myself.
I expect a lot of myself.
Could be applied to any occupation or activity.