Indeed, the clitoris was created for pleasure, but since it is an incredibly sensitive organ which has a huge number of nerve endings, it's prolonged direct stimulation at the same rate and in the same way can result in a temporary desensitization.
You may feel that you have lost the ability to be aroused and reach orgasm, but after a while, everything will return to normal.
A loss of sensitivity for a longer period can be caused by menopause, breastfeeding, or taking hormonal contraceptives, etc.
If you are very concerned, you can always turn to an experienced sexologist for help.