How to account for daily vomiting (due to illness) in calorie counting

Thank you all so much for the replies.

To elaborate on my particular situation, the issues began over a year ago. It started with 3 weeks of severe vomiting and abdominal pain (inability to keep anything down whatsoever) which caused severe dehydration and 40 lbs inadvertently falling off within those 3 weeks and I finally went into the ER where blood work determined my kidneys were failing and body was septic (hospitalized end of May 2016). They never determined the cause of the renal failure, though it was potentially due to a very prolonged klebsiella pneumoniae UTI. My renal function bounced back within a couple days at the hospital after being on antiemetics, pain meds, fluids, and antibiotics, and has maintained strong numbers since. Though this hospitalization has been followed by a multitude of varying bodily infections (viral, bacterial, and fungal) and the constant nausea/vomiting/severe abdominal pain has persisted with no known specific cause. My blood work, which I have to get done every 1-2 months or more, has been mostly normal with the exception of elevated CRP a couple of times and sometimes indicators of infection. My docs have obviously ordered many imaging, blood, etc. tests as would be expected, but nothing conclusive has been determined. I have another Nuc Med scan coming up to confirm a suspected kidney abscess on the right side. In addition to this I have a weaker than average immune system per a combo of severe sleep and other disorders which doesn't help any of it.

I am on 3 antiemetics (antinausea) which
absolutely help, though I still vomit almost daily. Again the timing and frequency is random though I have only had a couple of days in the past few months that didn't include vomiting. The severe abdominal pain is also fairly constant especially on the right side and I've spent most of the past year bed-ridden.

Following my initial hospitalization, I immediately gained some weight back per fluids and the ability to eat more/keep more down with new antiemetics, and I then ended up putting on a fair bit of weight last fall as I had about two months where I was vomiting far less frequently for whatever reason and I was eating a lot. The vomiting returned to a high frequency, though my body has assumedly been in starvation mode as my weight hasn't changed much since going up, despite the fact so much comes up, and I hardly expend any calories due to being bed-ridden so often. Due to this I started counting my calories more recently as being overweight doesn't help the ongoing health issues, but I'm trying to ensure adequate nutrition and to get to a more comfortable and healthy weight. For many months I avoided this as I felt counting cals should be my last priority, but at this point the cause of my illness still remains undetermined and it's been over a year so I'm trying to be proactive with regards to something I can control.

Again determining the cause of my symptoms is very important to me, as is maintaining adequate nutrition, especially at this time. However I also think it is important to reduce my weight both for physical and mental health needs as my weight is quite high. I worry that my cal and nutritional tracking is completely off due to food regularly coming up, so I'm hoping someone has an idea of how to account for such.