To day started off fine I left my friends house then went home and suddenly I was just really depressed.I mean a lot of things happened in the past week but they were nothing to get worked up about alex being engaged abigail not talking to me and my best friend being the same arrogant little prick he is but this is normal.so why am I suddenly sad!?

well, its hard to tell, because i dont know you. but, it happens to me, too. it also seems to happen to at least 2 of my friends. you could be stressed for some reason. from experience, though, i would just say that it just happens sometimes.