In your case, waiting 9 weeks between treatments is longer than typical recommendations suggest. Given that you are experiencing major toothache now, this could indicate an unresolved issue from the first treatment or a new complication such as reinfection or inflammation.
It is crucial to communicate your symptoms clearly with your dentist’s office. If they are unable to see you for another 5 weeks but you are in significant pain, consider seeking a second opinion from another dental professional or an endodontist (a specialist in root canal treatments). They may be able to provide immediate care or advice on how to manage your pain until you can receive further treatment.