I cannot offer an explanation or insight, but I can offer you a shoulder. I too got through the same. If my bf doesn't answer, I panic. I think he's avoiding me. Instead he's probably just really busy.
When he has a late appointment, I battle even more because I have to spend a while at home on my own, and again think he's avoiding me.

When my friend doesn't e-mail me back, I think she's ignoring me - in reality she actually just has a LOT of work on her plate! And may not have checked her e-mail lately.

I think especially when you are depressed, your mind just doesn't react correctly. Cut yourself some slack - it's hard enough to keep your own head above water during these times.
I was feeling very down and stressed yesterday, and driving with a friend, who got some irritating and stressful news. I actually just felt blank - I knew I ought to say something uplifting, but couldn't pick my own self up.

Be careful of continuously apologising and pushing people away, especially if they know you suffer from BP. In my experience, they actually do understand; if you get too much for them, they will naturally just shut down for a while. I think I've pi$$ed people off more with my continuous apologising.

As you come to terms with the dx and get to know yourself and your moods better, you will pick up on these traits and learn to deal with them.

Hang in there!