I think this will actually be a really good opportunity for you to learn about yourself, actually.

It's ok to feel hurt, about both the lack of response and her admission that she didn't have time. You're also right that it's a bit unreasonable to really hold it against her - you're forgetting that she's human and actually does have other obligations.

But forgetting that about her is also alright, because when you're seeing a therapist it's like the two of you are in your own little bubble, and we put a LOOOOT of trust into them to not hurt us like other people have hurt us. It's really easy to see someone as just their role, and forget that the little bubble we see them in isn't their whole bubble. (Think of how many students forget that their teachers are people, or how people forget their parents are people, or cops, or doctors...).

Have you had a lot of instances in the past where people have said they'd be there for you, and then weren't? I certainly have!! Way too many to even count or recall anymore. So even when it's something minor (like say, someone being ten minutes late) I'll end up upset and feeling like I just want to withdraw from that person completely. I know it's not reasonable of me, but I feel it anyway. I just opt to not punish them for it because I know it isn't really fair.

But feelings are always valid. You'll probably have loads to talk about with your T!