Not Getting Enough Calories

If you want to gain weight, you need to make the effort to get the calories in.

In what way do you "get sick" from consuming a certain number of calories? I'm not sure your body works like that

Make a bigger breakfast, take a smoothie (or other liquid calories) and some snacks for on the way to work (granola bars, nuts, dried fruit, trail mix etc), drink more calories at work, pack a snack for on the way home after work, then have dinner and dessert.

Pre planning your day will help you I think!

Try eating twice a day, one meal for breakfast and one meal for supper. 1000 each calories...if you want to gain weight, you're going to have to find a way to get your calories in and since eating small meals seems impossible from what I read, your other option would be to eat at breakfast and supper or maybe have a small snack 1-2 hours before supper if eating 1000 calories in one meal is too much. Not sure how we can help you if you have nausea over a certain amount of calories which is the first time I hear of this. Something tells me that it's more mental, if it really persists, I can only suggest you to have it check with a doctor.

Here is a meal example I can give you if it helps:
For breakfast:
2 cups of cereals of your choice + 1 cup of milk mixed with 2 scoops of protein powder, a banana will give you roughly 1K calories depending on the fat content of your milk. If that makes you sick, then you should seriously see a doctor, because it's not a common thing, you either have something physical that needs to be treated by a doctor or it's all mental.

For supper:
3 tortillas with 3 extra large eggs, 3 turkey bacon, 28g shredded mozzarella along with a cup of 100% orange juice (or chocolate milk if you prefer)

These are just samples, you can adjust the food to your liking. I mean I don't even know if you're following a ketogenic diet or vegan or if you have any allergies. This is just a sample of what I eat on a bulk and it might inspire you to come up with something else. It's not hard.

Why are you 85 lb?

Why is a doctor involved? Why is a doctor conflating their credential with that of a nutritionist?

Is the Nutritionist really a Doctor as "Doctor" is used in the U.S.?

Take a peanut butter and jelly sandwich with you to eat on the way. Not that filling, but can be about 5-600 calories.

To the 14 year old, you have to be 18 to be on this website.

How about eat breakfast at 8. Bring nuts to nibble on at work. Eat a little something as soon as you get home. Eat dinner. Eat a snack before bed. Eat more often on the weekend. Focus on calorie dense, low volume foods in the link above.

See if you can get a referral to a gastroenterologist, there is no reason a healthy woman should be physically unable to eat more than 800 cals. The only other option is that the issue is psychological, and if that's the case you should be able to get a referral to a therapist.

Best of luck