How do I cope with fear of getting a colonoscopy and endoscopy next week?

Speak to your doctor. Fear of an unknown procedure is natural. Having undergone the procedures myself I can tell you they are straightforward, take literally minutes, are performed in safest possible settings, & typically with you well sedated. Trust the skill & experience of your physician, & years of worldwide experience that backs the exams. Call your doctor if? 's of scope cleanliness, sedation, & personal concern.
Nothing to fear. To paraphrase jfk, you have nothing to fear but fear itself. The procedure itself is not painful, you will be anesthetized. Big picture wise, you are being proactive about your health, taking an excellent preventative measure.