The speaker is taking back a confession. They once told someone they were into them, but now they brush it off as "the drunk me," as if that version of themselves was a different person who spoke out of turn. It's a way of disowning the feeling without quite admitting it was fake.
The last two lines shift the tone. The speaker now has nightmares about this person, and says they were "just a dream for the night." The word "dream" appears twice, first as something that haunts the speaker, then as something fleeting and unreal. That suggests the attraction may have been a passing moment, one the speaker now regrets or fears. We can't tell exactly why it turns into a nightmare, and the poem leaves that open.
The mood is short, blunt and a little uneasy, mixing embarrassment, regret and a wish to move on. The brevity makes it feel like someone trying to close a door quickly.