I am having an endoscopy and an colonoscopy the same day,?

I am having an endoscopy and a colonoscopy both together and i am terrified, i am a highly anxious person who suffers panic attacks, i want a general anaesthetic but they say no. I am scared of gagging and being sick when they push the camera down my throat and the colonoscopy sounds awful, i am so scared , has anyone had these procedures and how did they cope?