10 years with the lap band, it's not full and I can't get any food or liquid down, what do I do?

You need to see your surgeon to have them evaluate the band. There may be a problem with the band such as slippage or even some scar tissue that has developed under the band that can create a stricture or tight area preventing food or liquids from passing through.  Your surgeon will likely try to empty any residual fluid in the band and set you up for an study where you drink dye and they take X-rays to see if the dye passes through or not.  You might end up needing an urgent surgery to correct the problem.

if the band is completely empty, and you cannot keep liquids down, this suggests obstruction from a band slippage. this needs to be evaluated by a bariatric surgeon ASAP so treatment can be determined and initiated

Based on your description, either your band has slipped, or you have concentric pouch dilation.  In either case, you need an operation.  I would get an upper GI x-ray to see what the problem is first.  My recommendation would be for simultaneous removal of the band with conversion to another operation such as sleeve gastrectomy.