our job as parents is to grow and nurture our kids into functional independent adults. It just got here quicker than you thought it would
Be proud, encourage and yep, time to let go. I've had to do it too, then you relish being very proud of the independent person that they've become and your relationship is different, but wonderful. You'll appreciate it, even with the distance. And don't call every day! let your kid call you and if a week has passed, then it's ok.
We're now 20 minutes from each other, I give my daughter space, leave a phone message that I miss her, hope all is well and ya know what? She'll come over for days in a row with her friends and hang out, then we won't see her for 2-3 weeks, it's on HER terms, and I'm happy when she chooses us, and don't use guilt or other means to make it sooner. You'll find this more of value, trust me, been there, been wrong, fixed it and love how it is now.