You've still not told us how you access your Gmail account. Do you go to their website or do you use a dedicated email client or app?
If, say, you're using an email app (possibly on your phone), it might be that while the emails have disappeared from that app's local storage, they're still on Gmail's server. If so, opening your web browser (rather than the email app) and logging into your email account from the 'Sign in' link here
https://www.google.com/intl/en-GB/gmail/about/ might well find your emails.
We need to know whether your emails are missing 'locally' (i.e. from within an email app or client) or from Gmail's server itself if we're to be able to point you towards a full solution.