Don't worry. Whilst blood in stool is not "normal" in the sense that it indicates disease of some kind, it is a common symptom amongst those with digestive problems. Crohn's and Colitis can cause blood, but as mentioned above, so can haemorrhoids and other less serious conditions.
Just tell the doctor you've noticed blood in your stool, or that you're "passing blood" - the doctor will know what you mean and won't view it as an awkward subject. It's information that could be very helpful to your doctor when making a diagnosis or deciding what tests you need.
Your doctor will probably ask you to describe the bleeding - is it black or red? how much? how often? is it mixed with the stool? etc.
It's possible that the doctor may want to perform a rectal examination to check for haemorrhoids and other causes of bleeding. This is where you lie on your side and the doctor will insert a finger or a tiny camera on a scope into your rectum. It's not that painful at all - I've had lots of them! - just a bit uncomfortable, but very quick. It may be your doctor doesn't see the need to do this, and if you're not comfortable with him/her, you do not have to consent if you don't want to, though it could really help in diagnosis. You can also ask for a chaperone to be present.
They may also ask you to provide a stool sample so they can test for blood more objectively.
Or it may be that your doctor recommends a colonoscopy or other tests - which likely won't happen on the day, you'll get a later appointment - which can check more thoroughly for Crohn's and other conditions, and which provide a lot of diagnostic information.
They may want to do some blood tests, in particular for iron levels as bleeding can lead to anaemia.
I know you'll feel nervous, but this is all very routine for a gastro. doctor. The important thing is finding the cause of your symptoms as quickly as possible and finding effective treatment. To achieve this, some embarrassment and awkwardness is unavoidable, though you'll probably find that if you need any further appointments, you won't be nearly as nervous about them as you are about the first one.