To me, the song is about dealing with depression. Saying he forgot to take his medicine meant missing a dose, and that affects his mood. He's feeling "so-so" because he's neither happy or sad, he's caught in the middle because of the aftereffects of the medicine from the day before and the lack of one today.
But the medicine isn't really helping him at all, because he still feels lonely and lifeless. Everything's forced and he isn't motivated to do anything. He could possibly be giving up on life, and all he wants is to do is go to the place where he used to be happy.
To me, the song is about dealing with depression. Saying he forgot to take his medicine meant missing a dose, and that affects his mood. He's feeling "so-so" because he's neither happy or sad, he's caught in the middle because of the aftereffects of the medicine from the day before and the lack of one today. But the medicine isn't really helping him at all, because he still feels lonely and lifeless. Everything's forced and he isn't motivated to do anything. He could possibly be giving up on life, and all he wants is to do is go to the place where he used to be happy.