Hi Martin! Hope, you're already feeling better by now. Just wanted to add my two cents...
1. Food: Have you tried baby food? I was thinking of "HIPP Beikost ab dem 4. Monat", you know, those small jars...they have a short ingredient list (mainly vegetables), small portions, easily digestable... some other brands are organic, too.
2. D-Ribose: This gives me a little more energy. I'm up to 5g, 3x/day, dissolved in anything that I drink (mostly tea). I'm buying it in bulk at "Bulkpowders.de". Every now and then they have discount prizes up to 40%.... The "pure series" is without additives. (They have whey proteine and many other good stuff there, too)
3. Dizziness and nausea: This can have multiple causes, like low blood-pressure (from lying in bed all the time) but also from under-stimulation / stimulation deprivation (from lying in bed all the time, too).
If the latter is the case, you could try a little body-scanning, like: where do you feel your head touching the pillow? Left side, right side, back of the head... then you proceed to every other body part. Let go of tension. May give your brain some input about your actual position, so it could stop the dizziness/nausea.
4. Lab tests: I see you're having some tests. In case there are tests that your health-insurance is not covering and you want to do privately: I can highly recommand IMD Berlin. You can pre-order the blood-collection tubes (free of charge) and a courier service (Germany-wide, free of charge, too). I contacted staff members via email and phone, all responded very prompt and comprehensively. (My GP drew the blood sample and the courier came to my home.)
5. Hope you're back to base-line soon! Greetings from Kiel!
P.S. Your roomies are great!