28 days late on my period

Brittany
1. I'm not pregnant ( IM. A. VIRGIN! )
2. I'm irregular so I'm use to missing some days but not months or weeks! 
3. I have constant migranes and I looked up brain tumors cause I'm constantly looking up things that stop periods for long periods of times! 
Idk what's wrong now. I went to the doctor he didn't really say much to the issue.