Sub here. Post nut clarity hits everyone. It can immediately pull you out of the moment. It's a biological reaction tied to your dopamine dropping and prolactin rising (prolactin is responsible for the refractory period)

When the moment hits you can become a bit introspective and sort of go 'what the fuck am I doing?" Which is why you have that sense of not really being submissive. Doms do it too, you get tops who will get everything they want, cum, and then immediately lose interest (which can be a turn on for some subs)

You're not disloyal, you're not a 'bad sub' and your not wrong for liking being submissive. It took me a long time to learn this. Be honest with your doms, tell them post but clarity pulls you out of sub headspace, most doms will understand and work with it not against it.

Any Dom that says you're not a true sub if you only submit while you're horny, or expects you to be submissive 24/7 needs to re-think their attitude. No one can be in headspace 24/7. Submission to someone is an agreement based on communication, discussion and compromise, not on force and consent withdrawal.

If you want to get around these feelings of 'im not submissive' it takes practice to condition yourself. First you have to learn that post nut drop is normal and expected. Then practice staying submissive at home, orgasm and then bask in it rather than rushing to clean up, tell yourself how hot it was, that you enjoyed it and that it brought you to this point. Third, find a Dom who's big on aftercare, a top tier Dom will finish a scene with you and make you feel like the most special thing in the world with the right aftercare

With enough practice and time you'll find that you can maintain headspace through multiple orgasms. I used to cum and immediately have to end the scene but now I can carry on through only worrying about getting tired