frustration

I'm trying not to get fed up but I am extremely frustrated with my current co-worker. She has been really wishy washy about leaving the job, which seems to be what she wants to do. We are currently in a transition period where she's working a few days a week, and when she does, she bitches about everything and then once she has gotten over herself, will proceed to dive into work that I have been doing. I should appreciate her help on the loads of work that I'm doing, but I just feel like I'm being stepped on and resentful. I just need someone to hear me complain!
To top it all off, my dear high-school friend who was supposed to come visit me this weekend, and I've bought Yankee tickets rearranged my life for it, is refusing to commit. I got a text yesterday saying she may not be able to afford it. And then today she said she won't know until 6 tonight when she was supposed to get in tomorrow at noon.

Poor poor me. Ugh.