should i see a GP?

Nobody knows for certain whether or not we have any conscious existence after death, but many religious faiths teach that we have an immortal soul that transcends death.

Furthermore, even agnostics and atheists can interpret the scientific “Law of Conservation of Energy” (which is accepted beyond all reasonable doubt) in such a way as to conclude that: whatever constitutes our self-aware mind has at least a strong likelihood of being conserved, after the demise of our temporary physical forms on earth.

You come across as being a normal intelligent and thoughtful young girl. Few young people are totally comfortable with thoughts of their own mortality, or of death amongst friends and close relations.

The “panic attacks” you refer to may be within the normal spectrum of anxiety in response to such thoughts, or could be sufficiently extreme to be classed as a phobia that could respond favourably to counselling or psychiatric treatment.

I have no doubt that a short visit to your GP will determine whether a specialist assessment by (for example) a child psychologist might be beneficial.

Perhaps you could book an appointment to go along with your Mother.