I accidentally deleted icloud backup, my notes are all gone, is there a way to recover them? Please help

There is probably no way to restore deleted notes, unless you have a backup of your computer that you can restore them from, and you had iCloud installed on that computer, and you were syncing notes to iCloud.

If you had Notes turned on in your iCloud settings on your iPhone they would be synced to https://icloud.com, and from there to any devices that were also logged in to iCloud. This is not a backup, it is a multi-device sync. And your notes would not be included in an iCloud or iTunes backup of the phone.

If you did not have Notes turned on in your iCloud settings then your notes WOULD be included in an iCloud or iTunes backup, and you should be able to restore that backup.

The important thing to understand is that an iCloud backup is not the same as syncing to iCloud.

You say you deleted your iCloud backup, but the notes should still be on your phone. What am I missing?