Losing a pet is never easy for anyone.  I can honestly say that I wouldn't be able to handle myself no where near as well as you seem to be doing about it, if that were to happen to me.

I don't know what your problems are with your friend, but I hope that that gets better for you to.  During this time, of you trying to resist self-harming, you're going to need all of the support that you can get.  But it seems like most of your support is away, or having troubles.  I'm sorry that that's happening like that, but that's how it sometimes goes.

Thinking of how your cutting yourself will affect your boyfriend is good and all, but, even more important than that, think of how it will affect you afterward.  All of those feelings of guilt, and most likely shame, will only serve to make you feel worse about your current situation.