As you're using Instagram on your PC, have you tried to clear your browser's cache and cookies? Try using this recovery page to get a login link so that you can reset your password to recover your account.
Check your email address including your Spam and Social folders once the link was sent. You may have to wait a few minutes before you receive a message, and make sure that your mailbox doesn't block emails from @instagram.com.
If you've also registered a phone number with your Instagram account, you can try to use it instead of your email to get the login link.