The joy of best friends.. You can spend years being the best of friends with all the chemistry and in the world and then after spending a few days living under the same roof you might want to throw them out the window lol. Unfortunately this happens a lot. Some people just aren't as compatible as roommates as they are as friends. I guess another reason that is is as we get comfortable with people we aren't as skittish when it comes to arguing.

From what you shared with us I don't think you did or said anything wrong. Also, from my interpretation you were saying that she injured her knee at work before the incident with the dog ever even happened, right? If that is the case then she really can't blame you or your animals because she already had an injury there and this particular incident just flared it up. Either way it was an accident, but I think it's silly to blame you or the dog if she already sustained that injury before.

I am thinking she is just frustrated which is understandable because no one wants to struggle financially, but that still doesn't mean she should take it out on you. I would try discussing it with her, but if you two can't find common ground then it might be time to just be friends again and look for a different roommate. It seems like something that should be able to be worked out though, with a little understanding and cooperation.