I agree with both of the above comments, but would like to add that you have to remember that your current TSH, since you are on Thyronorm, reflects a MEDICATED result. It in no way indicates what your TSH would be without meds. Chances are very good that your TSH would rise if you discontinued meds.
Why do you think you should discontinue thyronorm with a TSH of 3? That's still on the high side, but you also need Free T3 and Free T4 tests done to see what your actual thyroid hormone levels are.
is TSh the ONLy test data you have? Do you have free T4 and Free T3 tests?
Finally how are you feeling?
it all depends upon the person. many people need to have their TSH BELOW 1 before they feel well. Others feel fine with TSH or 3. So it really is dependent upon the individual.
however you should know that using TSH alone is completely and utterly insufficient. Unless you are extremely lucky the chances that you can adjust your thyroid meds on TSH is EXTREMELY small. You will almost assuredly be kept not feeling well by a Dr who insists on using "immaculate TSH" belief.