One of my friends (mom of one who Cloroxed her daughter's toys every night) asked me if I was "worried" and "lonely" when each of my kids went off to college. Sure, I missed their presence, but I was not worried, and they came home too frequently for me to be lonely.
All of them graduated, two with advanced degrees, and they continue to be successful, hard-working, fun-loving, and delightful parents to my grandchildren (who are also delightful)! I rest my case.