As far as I know, other than haemochromatosis, ferritin could be elevated due to excess iron storage or inflammation. You could have a CRP (C-reactive protein) lab run to check for inflammation.
My ferritin levels tested high a couple years ago and were a red flag with the practitioner I was working with then. I was advised to donate blood, and then my levels were retested. They dropped into the low range and I had symptoms of anemia, basically felt like crap and craved nothing but red meat for months. So whatever you do, be careful. Maybe stick with the blood donation for now, and have your levels tested shortly after the next time you donate to see how much they actually drop. And obviously pay attention to how you feel also. Did you feel any different after the blood donation? Better? Worse?
Since my last experience I haven’t worried about checking my ferritin levels again. I figure that “high” level is probably a good level for me since it dropped so significantly from one blood donation.