In just one line, the speaker admits that the last place they could escape to has been taken over. Dreams were supposed to be a refuge, somewhere to rest from whatever is going on during the day. But "you" has found a way in, and the speaker can't keep them out even while asleep.
The poem never says who "you" is. It could be an ex, someone who hurt the speaker, or someone they miss and can't let go of. The word "still" suggests this has gone on for a while and the speaker has tried to move on. The tone feels tired and a little defeated, with maybe some frustration underneath. The spaced-out letters in the title, "d r e a m," make the word feel stretched or drifting, like something slipping out of reach. The lack of punctuation and the plain, casual wording make it sound like a quiet confession, which gives the poem a lonely, haunted mood.