@Pollyanna88: It's possible that you have exceeded the storage quota for the Email app, which is limiting the amount of emails that can be synced to the device. With this in mind, please try deleting some emails, starting with your spam folder and sent items, then check to see if this makes a difference. You may also wish to check your sync schedule (3 lines > Tap the cog in the top right of the pop-up window > Select your account > Sync schedule) to ensure that it is set up to your preference. Although I understand that you have adjusted your Sync period, you should also adjust this to a lower timeframe, then check your inbox to see if this brings in the emails from that allocated period i.e. emails that are older than 3 days.
