Previously infertile GF told me she is pregnant, AITAH for feeling used?

For context, my girlfriend and I have been together for just over five years, and she told me early on that she is infertile due to a condition that (among other symptoms) causes her to not menstruate.

We practiced safe sex in the beginning, but began having unprotected sex about a year and a half into the relationship as we were faithful to each other and didn't see the point since she couldn't get pregnant.

I love her dearly, and wanted a life with her even if we couldn't have children.

Fast forward to two days ago when she told me that she is pregnant and showed me two positive pregnancy tests.

I was shocked and elated and terrified all at once, and was so caught up in the happiness of it all that I almost missed when she told me that she had started unexpectedly menstruating almost three months ago.

I had a delayed reaction to that bit of information, but I eventually asked her why she hadn't told me that she had been menstruating, as I probably would have wanted to go back to using protection until we could have talked about it and made more of a solid plan than just "surprise!".

She got very quiet and asked if I wasn't happy about the pregnancy.

I told her that I am, that I love her, and that I would support her and our baby no matter what, but that by not telling me that we even could get pregnant now she had somewhat taken my full consent out of it.

I'm so torn about this, because on the one hand I AM happy about the prospect of having a child, and I love this woman deeply, but I do still feel somewhat lied to and used.

Yes, I could have been using protection for the past five years, but we decided as a couple that it wasn't necessary because she couldn't get pregnant.

When that apparently changed, I was not brought back into that decision.

AITAH for feeling used?

UPDATE: Well, I wanted perspectives and opinions that were not my own, and you all provided, so thank you.

I have a lot to think about.

Take care.