WWW.
My condolences. It happens to some, some of the time. There is no magic formula I can offer. Think how bad it was for the CFI at Bournemouth who sent his student on first solo, and then had to watch him use it as an opportunity to commit suicide by diving into the sea after completing a touch and go. A pal of mine ditched in the sea, he survived but his student didn't. If they walk away it could have been much worse. Make sure you, the student and everyone else learn so as to prevent repetitive accidents.
Make sure commercial pressures, either from above or from your need for hours/cash doesn't influence your decisions on safety. I try to ask myself how I will explain it to the coroner and the wife and kids. If the answer is not right, stay on the deck and TEACH!
Sorry you had such a nasty so soon after starting out as an instructor. Just think of the fun as a QFI when it happens on a first solo that you send up. There but for........ .