Emails in yahoo Inbox went missing mysteriously

I have quite a number of emails in my yahoo Inbox. Most of them are emails I am yet to reply or emails that require my attention. Everything is fine until yesterday. When I logon to my yahoo account yesterday, it showed 0 message in my Inbox. It is the same thing today. I am really confused, where do my emails go? I never delete them (that’s why they are still in Inbox) and I am unable to locate them anywhere in my yahoo account. I really need help to recover my emails as they are some important messages in there. Thank you very much.