Sophie,
Hello - none of the members here in HealingWell are crazy.
Synesthesia can involve any of the senses. The most common form, colored letters and numbers, occurs when someone always sees a certain color in response to a certain letter of the alphabet or number. For example, a synesthete (a person with synesthesia) might see the word "plane" as blue or the number "4" as dark brown.
From what I know there are lots of people with this same problem and some of them have been famous people. You are not alone so please do talk with your Dr. re how to deal with this problem.
Kindly,
Kitt