What you are feeling is entirely natural. Your poly life is going through growing pains by the sound of it. Everyone is establishing their spot and trying to get comfy. Now is the time to voice what you need and your opinion on how things should be done.... things fuck up, but that is the learning part. It's important to be gentle with your judgement of yourself I think... you are being accommodating but also have your own ideas and needs... you are figuring out hers and she yours...
Ask constantly if she is okay with this that and the other thing and foster an atmosphere of communication. It's not okay for her to blow up at you about everything, but some things will trigger her too. Take a breath and talk to her about that. Ask her, "what can I do to help this process," "what is it that you need from me so I don't ruffle your feathers on certain topics and ways of doing things..." tell her that you intend to try and remember that she is getting to know you and that means that you have to be patient. Ask her to also be patient with you.
Keep talking about voicing these questions... hell, show her this thread if you don't have the words.
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