Well, you did it and can't untext it. So don't worry about it! Don't beat yourself up.
The next time think about it 24-48 hours before you start texting so you can decide if you really want to send it.
What's done is done. It's hard to act like a robot and not show feelings all the time. It's unrealistic of him to think you would be thrilled also after all of this. Hope your week gets easier.
