Middle age blues

Hi, I’m 51 and feeling a huge hole in terms of having fun in my life like I used to and having things to look forward to. All I do is worry about money, not having enough for college in a year, or this weird feeling like, “Is this it?” I have my own business and wish I could find a way to get excited about growing it but I wake up unmotivated. Like, what happened to the woman who traveled the world on business trips prior to having kids, lived in NYC by myself and had so much fun. That person now just does the same thing every day. I sit in the kitchen and try and do my work while the kids have virtual school only until 12 and then the rest of the day is boring and slow. How can I get myself back? I miss who I used to be.