It is very common to get different results at different times with the Myers-Briggs test. It’s a notoriously unreliable test. With personality dimensions most people tend to cluster around the middle of the scale, so dividing the scale rigidly in the middle and into types based on this isn’t exactly a good approach. The Myers-Briggs is not a good personality test. The five factor personality model (OCEAN) is the most popular model in personality psychology and is much more valid and reliable than the Myers-Briggs . It is based on factor analysis.