hey! m 5'8" too and i weigh 140 lbs. i used to weigh around 155... its okay to weigh that much unless you dont feel confortable at that weight... i know i didnt so i lost the weight...i cut down on the sweets and junk food and ate less and exercised a lot and it took me awhile but i got down to 140 and it feels nice... now im just working on toning up ...good luck if u nee me email me