Why i have 13 hidden courses?
Don't worry - your "hidden" courses are not actually hidden! The system shows them as "hidden" courses as they do not all fit on the course page. Library topics also count as courses, and every enrolled user has complimentary access to these, which is why it may seem as if you have more courses than you think you do.
There is a way to access the hidden courses. I am guessing you saw the "Hidden Courses" script because you clicked on My Content - however, if you click on the small arrow next to My Content, the course menu will drop down and be displayed on the page, where you can see all of the courses you are enrolled into (you will also notice one of them is Library).
I hope this helps!
Remember, if you require any assistance on anything iKnow related, please do not hesitate to contact me at firstname.lastname@example.org and I will be happy to help.