Itching after colonoscopy?

hi i am a 21 year old female for the past month or so i have been having bloody and mucusly bowl movements(some times only blood would come out) so as you could imagine this was very scary for me. I went to the GI who told me he would like to perform a colonoscopy on me to see exactly what was going on. he said it could be anything from as harmless as a bacterial infection( which i hoped it was) to ulcerated colitis or crohn's. after the colonoscopy he told me i had stage 1 internal hemroids and didn't know if i had ulcerated colitis, crohns, or diverticulitis, or just a bad infection(from a bad case of food poisoning). he then told me i would have to have some blood test done to find out exactly what i had. i didn't understand why i could not have taken the blood test before the colonoscopy this made no since to me. i feel like my doctor is very indecisive. Any way after the prep i was pretty raw down there despite using Vaseline and baby wipes. but recently i have started itching in my anus as well as burning in my Perineal area after a bowl movement or even just peeing. im worried i could have gotten some kind of yeast infection or tear from the colonoscopy it self please help.