What Causes General Weakness, Extreme Leg Fatigue And Muscle Pain?

I am a 51 yr old white female of italian and english descent. Weight 116 height 5 feet 0 inches. Have given birth 5 times. Meds are metaprolol succinate 25 mg daily, & xanax 3 mg daily,folate,vit d and b12 always super healthy and tons of energy until 4 yrs ago and still no answers.my symptoms first began after a trip to the beach four yrs ago.walked a good deal.I woke up the next morning in excruciating leg pain.felt more tired than I ever had. I have seen many specialists to no avail. I have majorly declined in four yrs. These are my constant symptoms in order of disturbance.I barely can function. Generalized weakness..extreme leg fatigue and muscle pain that recently feels like its in the joints as well.body aches and fatigue. I feel like I have a flu many days.. dry eyes. Dizziness at times verigo.unbalanced.vision fuzzy. Foggy and spacey. Today sore throat with bad mouth and tongue pain.can't walk well and everything I do is a huge effort.I get very drowsy and often at night find I have fallen asleep sitting up on couch.my daughter has to wake me.I am beyond frustrated.I am