My son was diagnosed with crohns when he was 8 [ he is now 20 ]. We went through two years of hell with not being able to get a diagnosis, but finally saw a doctor who agreed to run tests and found he had crohns all through his digestive tract [ mouth through to anus] with multiple ulcers and inflammation. He was started on azathioprine, pentasa and steroids.
Bleeding never was, and still isn't symptom my son had. He had constant stomach pains, fatigue, foul breath. He was also getting lots of night terrors and sweats. So much so I was having to change his bedding at night.
Flare ups can run for a long time if not taking the right medication, and even sometimes then flare up can happen.
As someone said the drink for a colonoscopy is revolting! It was extremely hard getting my then 8yr old to drink it. Don't mix it with anything red. You can drink things like 7up or Sprite, but no coke.
Things will move very quickly once scopes are done if they find IBD. You will given results on the day. If they take biopsies these will take longer. The first step nowadays is often a liquid only diet for 6/8 weeks to get the flare up under control, something like modulen or fortisips, Boost. There are others now but I can't remember their names off hand. These work really well, but can be tough to do.
Keep up a low residue diet, anything white, bread, pasta, rice. Fibre can make flare up worse, so low fibre.
You will be sent to a paediatric gastroenterologist and get assigned an IBD nurse who will be your first port of call.
CICRA [ www.cicra.org/] are very good, crohns and colitis UK. Also check out uk parents of kids with IBD on facebook, they give excellent advice for parents.
PM me if you want to discuss more. I have been living this almost 12 years now, so seen most things regarding IBD. Good luck, it is very scary first going through this. Luckily there is lots of help out there. Twelve years ago when my son was diagnosed there was no social media help when a child had this, which made it very lonely dealing with it on my own.