Multiple symptoms, what could it be?

hello everyone my problem started on oct 3rd, I had sudden diarrhoea, stomachache, nausea and fever ranging from 37 to 38 for a day. I was sure I contracted covid-19, due to my colleagues at work getting down with it even tho I was working alone, with no close contact. I reported myself in the covid ambulance, they told me that there's no need to get tested because my symptoms are not typical for covid, I did a rapid antigen test anyways, it came back negative. I went to my dr. did CBC, white blood cells were in a normal range but my red blood cells were low... erythrocytes 3.64, hemoglobin 111 and hematocrit 0.346, CRP 19.2 but erythrocyte sedimentation is within normal range, 10. I don't have anemia, my hemoglobin has always been around 165. 2 days ago I noticed my sense of smell and taste got weakened, I barely can sense anything unless I try too hard. My dr. ruled out covid-19 due to my normal white cells count, she said it could be food poisoning, cause I was drinking and eating milk, cakes and beans that day, but how can that be related to my loss of smell and taste, unless I have secondary disease, cold but wouldn't it affect my white cells then? Any help what it could be, please?

have you been tested for celiac disease

and you should have an endoscopy done if its not gone within like 3 - 4 weeks

No I haven’t… I’ve been eating gluten food all my life and I’ve never had problems with bread, only milk makes my tummy loud and gassy… Before this I’ve taken a CBC in June this year which was within normal ranges, my hemoglobin was 167 and my other red blood cells were normal. I mean, is a fever indicative of celiac?