Crohn's Disease( embarssment at school)?

ok now my doctor wants to give me a nasal gastric tube (tube up my nose) and have it up there for 6 months i am affrad my friends wont want to be my friends any more and people will stare at me at school and the shopping centre how can i handle that ? And my doctor also wants to do another colonoscopy and for that to flush me out he needs me to have 4 letres of salt water stuff that tastes discusting so another way to do it was to put the nasal tube up there to get the salt water stuff down. But last time they gave me a nasal tube i was awake and they got the back of my throat and i was throwing up blood. so i wanted to be put to sleep for the colonoscopy and wile im asleep for that they will but the nasal tube up but there's 1 problem i have to have the salt water stuff and im not going to be awake for that so how am i going to do it?