This is a really weird feeling that actually kinda frightens me.
Let me explain you, I really usually feel like I have a lot of personalities, for example when I am with people I don't know I feel really extroverted, funny, light-minded and outspoken and this kind of fades as these people become my friends and I kinda get more and more annoyed, introverted and even not nice to be around.
With my partner I am the complete climax of the last "personality" I described, as I get mad and upset very very often and I am completely unable to hide my emotions. I even feel a lot more annoyed by things that when I am the "extroverted" persona do not bother me at all.
Then there is the persona I have in my family, which is basically really REALLY introverted, scared and sensitive, yet not very empathetic towards the member of my family.
Lastly there is the weirdest persona I guess, which is kinda careless, apathetic, sarcastic and pretty funny I've got to say, in these moments it is really easy for me to talk to people in a very detached way and I feel like I am more capable of writing and speaking properly, if it makes any sense, cause usually I have a lot of troubles to express my thoughts and feelings. This is pretty rare but it shows up after deep emotional breakdowns.

Ofc this is a bit of a summary, I just said the main aspects of all of these personas, however it is incredible to me to think that my brain can shift so much from being sensitive af to completely apathetic.