On most phones, when you enter a new contact, it will give you the option to enter it into the Phone Account or your Google account. The option should be at the very top of the contact entry page. It might default to the Phone Account first, but if you select your Google account, it might remember that the next time.
You can tell if all of your contacts were associated with your Google accounts by going to your Google Contacts page on your computer's browser (google.com/contacts). If you see them there, then they're safe. Go back to the Contacts app, tap Menu>Contacts to Display, and make sure it's set to display the correct accounts and the correct contact groups. Also, go to the main System Settings under Settings>Accounts-Google>[your Google Account] and make sure Contacts is checked on.