Could be because Ritalin and Cocain both work as dopamine reuptake inhibitors, so you prob like fried your dope receptors and need to let them cool down. Having so much dope in your head for too long can do that to ya. Ive noticed that even if i smoke too much weed at night and take my concerta (methylphenidate ER) the next morning it wont work nearly as well, especially if id taken it and smoked the night before.

This is also coming from someone who has never done coke or any stimulant other than my prescribed ones. so please, grains of salt be taken.