I forgot my email... Please Help me

You would need to contact support. As long as you can verify that you are the owner of the account, they can get you the email. 1-800-4my-xbox if you're in the US/Canada or
support.xbox.com/contact-us

If there is a payment option on your account such as a credit card, that would be your last lifeline to recovering your account. If you can ring Xbox Support again and confirm the credit card on the account as well as your identity and details, they may
be able to help you out.

Source

How do I recover my Microsoft email after migrating my Minecraft account? I forgot the email please help me quick!!!! I migrated my account months ago and I don't remember my email. Please help me I'm begging you guys.

KingShot100

You can even contact MicrosoftOr you can go to the verifications steps to retrieve your account

If you know the gamertag and Xbox support can verify ownership of the account. By sending an email or text with a 6 digit code that they would type into their system to any email or phone number on the account then they can give you the email associated
with the account. The problem is it does not show them what email or phone number it is being sent to it just has them hit a button so if you do not have access to any phone number or email on the account you would just have to try and remember what email
was used for the account.