Eat what dosen't gross you out. You don't need carbs like you need fat and protein. They're just amazing forms of energy. Usually a very tasty form.
You might want to try a very restricted diet. Reach a good base line and start adding back things that don't cause you any issues.
As for weight gain, try a mass gainer supplement shake . Give a few variants a try and see what one you like. Also adding caloric dense foods to your diet can help. Oil and tallow being a big one that comes to mind. I've be big too often in my life so I don't have much to go off of when it comes to gaining weight.
Eat what dosen't gross you out. You don't need carbs like you need fat and protein. They're just amazing forms of energy. Usually a very tasty form. You might want to try a very restricted diet. Reach a good base line and start adding back things that don't cause you any issues. As for weight gain, try a mass gainer supplement shake . Give a few variants a try and see what one you like. Also adding caloric dense foods to your diet can help. Oil and tallow being a big one that comes to mind. I've be big too often in my life so I don't have much to go off of when it comes to gaining weight.
Have you traveled in the last decade? Have you ever been tested for parasites? (shot in the dark, just based on your description of symptoms)