scared about ME/CFS

good day everyone.
I had mononucleosis almost two years ago and I have been experiencing relapsing profound tiredness that last for few weeks.
After mononucleosis I was bedridden for couple of weeks, having fainting feelings and extreme lightheadedness. These symptoms slowly improved and I was able to go back to my normal working and social life with a good level of energy with just occasional profound tiredness that lasted just couple of days though. One year after mononucleosis I started doing sport intensively for one month and I was feeling pretty fine even though lightheaded(this symptom never left me since mono).
After this month though I had another crisis lasting different months always going back to pretty normal living quality but having again crisis after long trips and phases of high exertion. Lately, after I just went back to normal living quality for 10 days, and after working and having a pretty tiring trip, I had another flare up that left me basically completely housebound for 1 month and a half and it’s still continuing. I don’t have pains, headaches, flu like symptoms and all those other symptoms I have been hearing but I’m scared to have ME/CFS. I did many blood tests, MRI, cardiologist check etc and they didn’t find me anything. Just low circulating iron and pretty severe esophagitis due to reflux.
thank you to whoever will reply