My e-mail box is full but I can’t access my archived mail and only have less than 800 e-mails, what gives?

Several months ago in an effort to save space I archived about 4000 messages from over the last 5 years thinking it would help. Now with only 800 in my inbox I’m getting a message saying my inbox is full. My Google Drive is showing 1GB while my gmail is showing about 14GB. I’m assuming it’s my archived mail causing the problem but nothing shows up when I go to Archived Mail or All Mail. I’m worried now that all those e-mails are gone forever and I’m not sure what could be causing the backlog, please help!