Prednisone is a steroid (an analog of adrenalin) and messes with the hormone balances in your body.

From the Merk Manual:

Dependency

Adrenal suppression will occur if prednisone is taken for longer than 7 days. This will cause the body to lose the ability to synthesize natural corticosteroids, resulting in dependence on prednisone. For this reason, prednisone should not be abruptly stopped if taken for more than seven days, and instead, the dosage should be gradually reduced. This weaning process may be over a few days if the course of prednisone was short, but may take weeks or months if the patient had been on long-term treatment. Abrupt withdrawal may lead to an Addisonian crisis. For those on chronic therapy, alternate-day dosing may preserve adrenal function, thereby reducing side-effects.[4]

Glucocorticoids act to feedback inhibit both the hypothalamus (decreasing Corticotropin-releasing hormone [CRH]) and corticotrophs in the anterior pituitary gland (decreasing the amount of Adrenocorticotropic hormone [ACTH]). For this reason exogenous glucocorticoid analogues down-regulate the body's ability to naturally produce glucocorticoids. This mechanism leads to dependence in a short time and can be very dangerous if medications are withdrawn too quickly. The body must have time to begin synthesis of CRH and ACTH and for the adrenal glands to begin functioning normally again.

It may take quite some time for you system to regain it's center again, until then stick to indica "couch lock" varieties and you will be more in a more relaxed zone with your smoking.