Celexa was exactly what I was going to mention, but, of course, I am not a doctor, but there has a lot in the psych literature about using it for PMDD.
I do question the 5 miles thing. I once had my doctor tell me to ride 5 miles, when I was having medical issues that had nothing to do with riding. He also "was a cyclist," but he just had no idea that he was talking to someone who would have had real issues if I couldn't ride my usual miles. Of course stretching is good, and warming up and cooling down important. But, how does he know the route you were doing is "too hard for you?" That sounds like a real condescending attitude. Find a good PT who knows about cycling and can treat your injury.