Hi and welcome!
I'm so glad you told your saga of bad insurance policies, financial woes, etc. On other websites I meet people who desperately want and need bariatric surgery and have pinned their hopes on the DS, but have insurance like what you had and no other way to finance surgery. I express sympathy but also tell them to never give up hope. Things can and do change, and I'm so glad they changed for you. Your story will give hope to others.
You've already had some great advice about fat and vitamins and all, so I'll just throw in that 5000 D is a piddly ass and totally inadequate amount for someone, really anyone, with the DS. We only absorb about 20% of the fat we consume (which is why you can now eat fat freely) so we also don't absorb the fat soluble vitamins well. These are A, D, E, and K. No one seems to have trouble with E (now watch, someone will come along and tell me they had a problem with low E but really it's rare) but we need to supplement A, D, and K aggressively and with the "dry" form, because we won't absorb the stuff packaged in oil. 50,000 D per day seems to be the bare minimum. I now take 100,000 D per day just to stay in the mid-normal range, but you could at least start at 50,000 and see how you do. Get the dry A and K as well, you'll need them. I'll leave the rest for others who get into the details more than I do.
And, if you have a Costco handy, they have the best canned chicken around. the regular grocery stuff does not compare. You can make a nice chicken salad with that stuff - and with full fat mayo, of course!