I know where your coming from , but over the years I also know where the docs are coming from.
when i was younger always having food forced down my throat started to turn me off from food and made gaining weight a chore, something always lurking in the back of your mind when it came time to eat...
If your really struggling to gain, the doctor may recommend a g-tube, I know its not something that everybody is okay with cosmetically, but I can say that it has saved my life. when i got one i gained about 20lbs right away within a month or two. and when i wasn't that hungry i would add extra tube feed at night. when i was sick and the antibiotics made me lose my appetite i could tube feed during the day too, a lot A LOT less stress.
maybe the weight gain products like scandi ect, not enough enzymes or wrong kind? sometimes that can make your feel gross... or maybe just take half of the products, i know some protein bars i can't stomach a whole one at one sitting.
but i can't stress enough your body needs and craves more calories especially when your fighting infections!