Get together with other moms in your situation.. I went through this too. I called some of the other moms of my daughters friends and we met for Margaritas. We just talked about or kids and how they were doing and what our own plans were.. We talked about things we had always wanted to do, but couldn't because our children were always busy with school, homework activities.
I heard about a lot of good projects they were planning on doing. Some of my friends were teachers so I asked how I could help them. You could look into working part time or volunteering. Maybe take a class to learn how to do something you are interested in. Get on a new exercise program. Try Yoga. Think about the fall festivals you were never able to attend because of your childs activities..
Get on facebook and see if any of your old friends want to meet up. Get a friend to go and see a independent movie in the middle of the week. There is a local cafe has a "Trivia Night" once a week. We have a group of friends and meet once a week for an inexpensive dinner and play trivia.. It is a hoot. We break up into teams of 4 to compete. We all look forward to those nights.
We also have a moms group for moms of students that moved away to go to college. During the school year, we try to meet once a month for a potluck with wine and tea. We each bring something for a monthly care package.. If 10 moms are there we each take 10 of something. We then end up with an interesting collection of stuff to send to our children. Our kids feel like there is a community at home thinking of and supporting them. I have taking some of those 110 calorie packages of snacks, bandaides, teas, packages of mints, gum, crystal light packets, Rice Crispie treat packages, box of ziplock bags. socks, gloves. At Halloween some of the moms gave masks, tattoos, wall decorations.
We discuss the ups and downs our kids are experiencing.. we make suggestions, sometimes, we can offer a contact in that city or on that campus.
What you are feeling is very normal. Our daughter is over 2000 miles away and the ONLY thing that makes it bearable, is that she LOVES it and is doing so well.. She is thankful for her opportunity and we are extremely proud of her. You should feel the same. Good Job mom. This is what you were working towards this whole time.