Lyric discussion by soadfan8 

Cover art for Sick And Sad lyrics by Streetlight Manifesto

This song is about a girl he know who kills herself. If you follow along with the lyrics it makes perfect sense. it foreshadows death from the very beginning, mentioning "someone there who mentioned that they hoped that it would rain forever, forever, so they could drown in peace."

he hears this on the way to the girl's place, and when he gets there, ringing the doorbell "forever, forever" implies that he could literally ring it forever and she would never answer because she's gone and can't come back, and that's why now he's sad all the time.

"Today was the day but she threw it all away" this line is the differentiating point between the song being about suicide and just being about not having a girl. it doesnt fit with the latter. He can't understand why she did it because he saw them as similar people, trying so hard and never giving in. The difference is that ultimately, life got to her and she did give in.