Permanence or impermanence of joy, happiness, love?

Hello! There's something I can't understand, and I though you all could help me! So I started my spiritual path with Michael Singer, who says one can feel the shakti, the energy, flowing through one's body and that it gives a feeling of permanent happiness, joy, ecstasy.

At the same time, i listened to Alan Watts and he never speaks about it. I know he was partly influenced by buddhism, that states that nothing is permanent. Thus permanent joy, happiness, love etc is impermanent for them.

But the thing is, if I understood both well, who is the wrong according to you? If nothing is permanent, then why M.Singer (according to him, but he doesn't seem to lie) is always joyful etc?

Thank you so much!