Diagnosis Overshadowing?

Disclaimer: “Mayo Clinic has nothing to do with this situation at all. Please don’t delete my open discussion this could be life or death for me. Thanks! 🙏🏻”

Can someone explain me what it’s this term used for, what it describes, the criteria or the definition? I just learned about medical gaslighting but I don’t know if this two terms are related. I’m asking since I’m currently fearful for my life and health with the health services I have gotten over a year. Have anyone filed a complaint to the Department of Health before?

Please any help would be greatly appreciated.