Sometimes, when the firm understanding of no-self first comes upon you, it can unleash a vast reservoir of energy, especially if this understanding has dawned in a non-traditional context ie. without preparation of the body-mind.
That energy comes into and animates the body-mind, and energises it.
Sometimes negative, destructive, addictive and hedonistic habitual tendencies (vasanas) can be enhanced due to that injection of energy. We may feel negative or even euphoric, depending on the pre-existing conditioning.
Beware of this. Here the teachings on dispassion (vairagya) become more important than the insight (into no-self) teachings which have already begun to hit home.
Remember not to get involved or get carried away by such thoughts, desires, feelings and behaviours. Do not indulge in this (ego-) energy. The old ignorant habitual tendencies are still at play even though insight (into no-self) is here, and the suffering and potential destructiveness caused by them still has not been eradicated.
Instead continue to take up and press on with your sadhana: relax, remain calm, be still, allow all to come and go, be unattached, be as you are, until all the vasanas have gone. Then the sadhana will also go.