Why delete the number? She's definitely not sending you any negative signals or anything. She's got a lot on her mind, because of her reunion, so naturally the guy she just met isn't as big of a priority right now. But wait a while and she'll be back.
The only other option is that it's a complete blow off tactic (unlikely), in which case there's nothing I would recommend you can do, so who cares?
In either case, you had an awesome first date with a woman. Great! Find another one to have an equally great time with!
