Talk to General Physician on Prolonged Weakness

I am unmarried. I have been suffering from weakness spells for more than 10 years. In some days of month I feel good strength in me while some other days feel weak. I have got myself checked multiple times plus got all recommended lab tests done(i.e. CBC, serum TSH, urine analysis, LFT, CA++, vit D , iron, stool test) and all lab tests are found to be normal. In the meantime doctors prescribed multi-vitamins, iron, CA++ vit D and other supplements plus vit D, vit B injections but unfortunately nothing works . I still feel immense weakness episodes, face and hands remain pale, don't feel like doing anything, myalgia, fatigue, indigestion and flatulence, wrists and ankles are thin. I even take proper diet, eat dates, dry fruits, milk, yogurt fruits vegetables , often do exercise but body doesn't accept whatever diet I consume. kindly guide. Thank you