I joined a family icloud plan but I haven't cancel my personal icloud storage plan and now I can only see the family icloud plan account. What happens with my personal icloud plan, will it auto-cancel or will I still be charged for it?

Share an iCloud storage plan with your family - Apple Support

If you already had an iCloud storage plan

If a family member is already paying for their own iCloud storage

plan, they can choose to switch to your plan or keep their own and still

remain part of the family. When they switch to the shared family plan,

they get a refund for the remainder of their personal plan. They can't

keep their current plan and use the shared family plan at the same time.

The above is written from the perspective of "you" being the organizer but it does say what should happen to you as a family member with their own iCloud plan.