Hmm....

switching to and from each one whenever the mood strikes

I don't think I would want to live with those kind of mood swings! I do think it's cool that your creativity allows you to switch like that: I usually can only focus on one story at a time.

This is definitely blood and guts horror, and a little too much for my taste. I think you handle the flirtation, the dynamic of this group of friends, and the immaturity of the guys really well: all of that is really present and real in the story.