My bunny... THUMPS?

My bunny doesn't thump in the way I normally think of thumping...
If she enters my bedroom, which I don't normally let her enter, she
runs and then sometimes there a loud popping noise while she moves...
She does hit the floor... but why? She normally seems excited to be in the
new room... so how can she be agitated?

They can thump in excitement and for almost any emotion really. I'd just take it to be excitement if the rest of her behaviour and body language is telling you that.

Sounds like it might be more of an "I am here........pay attention to me now." kind of thump.