Nausea for Two Weeks

Hi All, 17yo female here. I have celiac disease and a history of anxiety.I take 10mg citalopram for anxiety. I recently traveled to Austria. I flew alone to Munich and the journey was extremely stressful, I had three panic attacks on the way. When I landed I missed my train and had to take a 400 dollar taxi to Innsbruck... basically, a very stressful journey. That night I felt fine but wasn't hungry really. The next morning after light exercise and being out in the sun I started feeling like I had a fever. Though I never took my temperature, I think I had a fever for a day or two. When I got back to the hotel room I felt extremely nauseous yet also starving (I ate nothing on the entire 24ish hour journey). I had panic attack which includes scratching myself, contemplating jumping out the hotel window, etc. Felt like I was about to throw up for hours and hours yet never did. Slept 12-14 hours for the next few nights. Was extremely hungry but whenever I saw food or smelled it I grew extremely nauseous. I expected to throw up many times but never did. Had diarrhea once, then no more bowel movements due to lack of eating. Took Zofran for the nausea twice, helped temporarily and then the nausea came back. I am definitely not pregnant. Took benadryl as well. I then took Valium. Went to a hospital, had an IV for fluids and also had Vomex in the IV bag. Took a flight back to the US (very traumatic, extremely nauseous the entire time, held a barf bag but never threw up) and went to a hospital in the US. Was given fluids. Then saw my therapist and psychiatrist. They told me that from not eating my body went into "Starvation mode" and stopped wanting to eat. They said my anxiety was causing the nausea. Forced me to eat, increased the dose of citalopram ( though it takes 3 weeks to kick in) and prescribed valium for panic attack/ extreme nausea, which I took twice but it made me really sleepy and extremely thirsty. Standard blood tests were done, and am going in for more specific blood tests soon (lyme disease, etc). I am extremely fatigued, unable to really eat, and constantly nauseous. Nothing seems to be helping, I have tried Sea-Bands, Zofran, sparkling water and more. I feel as though this is not anxiety because it began with a fever and hasn't happened in the past, and also because it is continuing for so long. I have been sleeping plenty, need to go to school because it's senior fall and important for college. Any guesses as to what I should try or what this could be (besides anxiety) would be extremely helpful. I am getting desperate, as this sickness is lasting for what feels like forever and I don't feel that I can go on for much longer.