Should I be concerned over B12 levels?

Just recently I had my b12 tested. My levels came back at 3568 ( no supplements and nor energy drinks being used). I know some people get anxious at a level of 1100 or even1300 and there seems to be no reason for concern. I have been pretty ill this year; being diagnosed with Myasthenia gravis and having a tumor in my chest, frequent infections such as bronchitis in mid July, etc. I do have slight low rbc of 3.94 and  wbc 3.1. I was told by primary care physician not to worry about my high B12, its just good nutrition. I dont have that great of nutrition! I would like to know should I have this investigated further? Or am I worried for nothing?
Thank you,
Anastacia

[Renee Radenberg]

There are no adverse effects associated with excess Vitamin B12 intake from food and/ or supplementation and no toxicity limits were developed. You may have eaten a high vitaminB12 food source before the blood test. Thank you for your question.

[wilkisons]

Thank you!!! However I am on no supplements and it was a fasting b12 that has been rising over the past year.