Advice?

Can someone tell me if I’m over reacting from these pregnancy hormones or if I should be a little upset?

So my Fiancé and I are expecting. About a month ago we were visiting his parents and found out that his adoptive sister was also expecting and due this month (December). She was/is/did have a baby boy. We did not yet know what we were having as we were waiting for the gender reveal.

So over small talk with his parents, his sister already had a named picked out for her newborn son and everything. We were/are happy for her. However, we had told his parents both of the names we had picked out if we were having either a boy or a girl. Sebastian for a boy and a different name for a girl.

A couple weeks after we found out we were having a girl and we are sooooooo excited. But I still want/wanted to use the name Sebastian for a boy if we had a boy in the future.

I just found out today that (congratulations to her) but she had a healthy baby boy and guess what she named him......SEBASTIAN!!! 😤😤😤 For some reason this angers me like she did it on purpose or stole our boys name!! Do any of yous think that’s odd or am I crazy?!