Tired, Tingling In Body Parts, Palpitations, Normal Glucose And Hemoglobin Tests,had Taken Protinex, Vitamin B, Consumes Healthy Diet. Remedy?

i am a male of 24years. my problem is that i use to tire after a little activity. my shoulders, upper arms and legs become more tired. i can feel my heartbeat( palpitation ) in my hands & other body parts. sometimes there is slight tingling in my any body part. my this problem is more than 2years old though there is slight improvement. my hemoglobin is 15, blood glucose-70mg and other tests are normal. doctors prescribed me supplements like protinex, vitaminB but all in vein . my this problem was started in march2010 before which i used to go gym regularly. I am not sure but i think my this weakness is due to over training in gym because shorty after reducing my wait, i stared heavy weight exercise. but such weakness should be no more because even now my diet is very rich containing at least liter milk products in a day. kindly suggest me solution of my problem. i would be thankful to you from bottom of my heart.