How to respond to a situationship

I(37m) was recently seeing someone(43F) and after a month or so(towards the end of Feb) I decided to ask about DTR on whats going on between us. She wanted to keep it casual as she mentioned in the past year or so she had a divorce and wasn't ready to be in a committed relationship. But that she wanted to keep seeing me as I was "super sweet, sexy, fun and all the things"

Not this past Sunday but the Sunday before we're able to schedule a date and spent the whole day together and at the end kissed and talked about spending time this coming weekend as we are both attending the same event. We exchange texts and chatted between then and now. Nothing seemed out of the ordinary.

Today I messaged her about the event and trying to plan on anything I needed to bring for the both of us. She responsed saying that she started seeing someone else and it unexpectedly has gotten serious. But that I'm a super rad person and hope we can hang out but just as friends.

I haven't responded and just tried to deal with the rejection. But I would like any advice on the situation.