Good morning, Courtney.
The anxiety causing dreams like this is a fear of losing your friends - not necessarily to death, but rather the loss of the relationship. In your dream both friends died in their sleep, which could indicate that you think they need to "wake up" to some situation in their lives, or you could potentially lose them as friends.
The only clue I get to what that situation could be is, you cried harder when you thought about the one girl's boyfriend. This may mean that the threat to your friends lies somewhere in their relationship with their boyfriends. Or it could lie closer to home, referring to your own boyfriend if you have one. It's difficult to get specific without knowing what's going on in your waking life.