As long as your terminal ileum isn't damaged you shouldn't be continuing to lose weight. When did you have your surgery and for what reason? What are you eating along with your Ensure?
Jan gave you a good suggestion with the banana/protein powder blended with the Ensure.
I was down to 82 lbs after I had my surgery and was very nauseous. My body was adjusting. I barely broke 90-95 lbs for several years. But just in the last couple of years I've finally gained a few pounds.
Keep asking and reading and trying different things. Have hope. There has to be something to help.
Jan - what protein powder do you use?
Dutches - here's a link to a product that I used for years to help maintain my weight. The only thing is that it is pretty high in fat so adding the banana helps to slow transit time IMO. Also, I was able to mix it with milk since I was not lactose intolerant. And it tastes pretty good, esp if you stick it in the freezer for an hour or so. The only other hint about it would be to mix like the night before you want to drink it so it has a chance to dissolve welll.
Hope this helps. It has several vitamins/minerals in it as well and doesn't taste like it.