Mystery Diagnosis-Post-Surgery?

I'm currently 2 months coming out of an anthroscopic ACL replacement (cadavor from an organ donor)-I am a 19 year old male and my pre surgery vitals were flawless-I'm athletic and in college-however, after surgery I began experiencing extreme cases of anxiety, this has made me drowzy, sleepy, moody but most of all anxious to the point were I get overly excited to wake up in the morning, I'm not much of a pill popper and never will be, but when I take a Xanax, I'm in heaven (and its a very small dose of .5 mg), my head only begins to have a right hemisphere pressure when I think about it or when I'm hungry (a possible sign of hypoglycemia). There is a slight possiblility of almost anything including pheochromacytoma, but I don't think xanax could silence an outburst of adrenaline, I recently had a 24 hr ysis of my blood pressure on a bad day and it came to be tensed systolically at over 130 80% of the time and over 140 61% of the time, but diastolic was perfect-any insights, thanks