Welche Bedeutung steckt hinter der hier vorgestellten Vokabel aus dem Bereich Office gossip?

Vivienne: 'I'm going to bed early tonight. I'm meeting the client for the first time early tomorrow morning and I want to psyche myself up for it.'

to psyche oneself up

Do you know what it means?

• to have a long rest
• to distract oneself by reading
• to mentally prepare oneself