Yeah. It’s pretty impossible to not be influenced by other people’s feelings, or to not influence theirs in turn, and it can spiral back and forth pretty quickly.
Are you looking for advice?
I’d suggest mindfulness — be aware of what you are feeling, and let the feelings come and go as they will — don’t try to hurry them along or keep them close. Don’t blame yourself for your feelings, however irrational or intense they may be.
Also remember that you don’t have to act on your feelings or blame the person who’s triggered them — you can be mad about her anger without punishing her for it.