You barely lost much fitness. It's only been about 17 days. Joan Samuelson (Benoit at the time) had knee surgery 2 weeks before the Olympic Trials in '84 and still won the Trials and the Olympics.
I recently missed three weeks while in the field (military) and ran a marathon three weeks after getting back. It probably had a small effect, mostly due to poor sleep patterns and less than optimal nutrition, but I ran 3:07. Hoped for sub-3:05 and was on pace until around mile 22 or 23. Don't let the missed time get into your head. Just trust your previous training. Like I've seen people post on here before, "The hay is in the barn."