iPhone 4 notes disappeared!

Can anyone help please? I went to look at my notes on my iPhone today and found that they are no longer on my phone! I have done nothing new to the phone - they are just not there. I have been on itunes and could not find it in my apps - the phone had automatically synced and backed up to my laptop. Thought I would try to restore the phone but the last backup was this morning and I can see nowhere to get access to older backups.

I have a lot of important info in the notes and would be very grateful if someone can tell me how to get them back.

Thanks in advance