You can feel however you want to feel. You already realize this is a "trigger" word for you, and that's an important awareness on your part. You probably even realize that she wasn't being abusive by using that word; she isn't your boyfriend and you realize that. But your reaction to it is what is important here. It would be worth discussing it with your T, not because she's "wrong" by using the word, but because it is an issue at your core that you need to process.