Hi,
I am posting on behalf of my brother. It's been 3 week as these symptoms started. We have performed a full-body checkup's and everything came good except B12 deficiency. I am posting here, seeking your help. Few thigs that he mentions - 
1. Pulling sensation in hands and feet with cold feeling
2. Fast Heart beat
3. Sleepless-ness , sleeps for 3-4 hours

Thank you.