Try turning your calendar syncing off (sync), then turn it on again (sync). If you are syncing directly from the PC's Outlook (it sounds like that is what you are doing) you should find the setting in the Info page in iTunes when you iPad is connected and selected.
No evens should be erased from you iPad doing this unless you go to the advanced section at the bottom of the Info page and select that option.
And if the first trick does not work, you might try that. Since it only deletes stuff from the iPad your original contacts in Outlook should be fine. Just pay close attention to pop ups that talk about merge/delete and such. If it starts talking about deleting stuff in Outlook or on the computer it would be wise to say no.
Most of us prefer to sync our contacts to Google. Both Outlook and the iPad can be set up to do this. I'm not familiar enough with Outlook to offer instructions, but here is how to do it on the iPad. As before, keep a close idea on popups about merging deleting things, and hold in mind where your good contracts are so that you do not delete them by accident.
Setting up Google Sync with your iOS device : Mail, Calendar, & Contacts - Google Mobile Help
If you choose to go the Google route be sure to remember and turn off the syncing on the Info page in iTunes. If you don't you'll soon be seeing duplicates and other mysterious errors every time you sync with iTunes.
