Kerry,
You are less than one week post op and pureed foods don't normally start until day 8. That could be why you are feeling nauseated. I would eat things that are liquid only for right now. Some people need to stay on fluids longer than others and you may be one of them. Do you have any meditrim left? If so, stick to that and some broth and maybe some jello for a few more days. Fear is normal at this point but life becomes completely normal once you are healed. You are in the WTF did I just do to myself mode. It will pass so don't worry about how you are feeling. You just had surgery and the nausea could still be from the anesthetic you had so if you feel a wave of nausea starting then take some gravol. In a few weeks, you will be over all of these feelings.
When I threw up with my band from having a GI bug, it was the same as vomitting pre band. Vomitting with the band if something is stuck is different as there are not stomach acids mixed in. The chewed food just comes right back up. Since you are on liquids, you wouldn't be stuck so chances are if you vomitted at this point, it would be like a regular vomit.