No, at the top it says "All Accounts". The Emails I received yesterday and today are there, but when you scroll down, all that's in the inbox are sent emails.
Are you on ActiveSync? My Exchange emails get deleted all the time and I have to turn "sync email" off and back on again (or delete and re-add the account) to get them back. A "known issue", it seems. Needs a fix NOW.
Is this is an Exchange ActiveSync account? Hotmail and gmail accounts are usually set up as ActiveSync accounts. If so, there is an advanced option named "Messages Sync Timeframe." I believe the longest sync timefame is one month. Messages are automatically removed from the PB when they are older than the sync timeframe -- however, this should apply to both sent and received messages, so this may not be your problem.
This happened to me today, all my incoming emails disappeared and only left sent ones. Several weeks ago, I had to start to reactivate the email account on a daily basis as it seemed to loose contact each night. Then several days ago I found that I was not getting all my emails. Today they were all gone. I deleted the email then reinstall it, the old emails did not come back even though I chose to go back 30 days. Strange.