Should I Be Mad?

Alright, my 'best friend's' dad died a year ago. Her mom has been a wreck ever since and gets mad easily from stress and what not. Her mom is very nice and works A LOT. Seeing as her mom is very overwhelmed i think it's normal for her to be mad. Today happens to be her mom and dad's wedding anniversary. Her mom is at work right now and will be home later. She called me asking me to come over. I saw that her kitchen was messy and told her that it would be nice if she cleaned up so her mom could come home and relax. So we start cleaning and then after a while she goes into her living room and starts to watch harry potter. She left me alone to clean her mess! She is my best friend and i love her like a sister but she has been so different lately.

She has a boyfriend who is now the epicentre of her world. for christmas he gave her a necklace. Yesterday when she was hanging out with three other guys (2 of which are ex-boyfriends) she broke the necklace. she left it on a table and this morning she couldn't find it. She was more worried about the necklace than making her mom happy! So i tried being a good friend (I'm sick by the way) and i tried to help but in the end i just couldn't take being treated like crap! I couldn't take it so i said sorry i have to leave i did some of the cleaning bye. She didn't really even acknowledge i left. So am i right to be mad?