gave my best employee a glowing reference and now she's leaving. did I play myself?

She's been on my team almost 3 years. Easily the most reliable person I have. Few weeks ago she told me she'd been approached about a senior role at another company and asked if I'd be a reference.

I said yes because honestly what was I supposed to say. No? She's been great and deserves the opportunity. Wrote a really solid reference.

She got the offer yesterday. Putting in two weeks on monday. Better title, better money, the kind of move I can't compete with on our current pay bands.

I told her congrats and I meant it. But now I'm looking at redistributing her entire workload across a team that is already drowning. My boss asked me what happened and I could tell by his tone he thinks I handled this wrong. No budget to backfill until at least next quarter.

I know saying no would have been a shitty thing to do. But I also basically helped her walk out the door.

anyone else been in this spot?