I was like that for a while last summer... For about three months I subsisted entirely on the bare minimum of food to keep me alive. No anorexia or anything.
None of the doctors I went to found anything abnormal ( well, I have 4 heart diseases and a liver disease, so it's always "abnormal"). Either way, the only method I used to increase my appetite was starting on very bland foods that had little or no aroma to incite nausea. After that I progressed to mainly vegetarian foods, and eventually back to normal. BTW I'm 6'2 as well and I ended up at like 138 lbs.
The worst part was that I ended up as a hypoglycemic because of the whole incident.