I am 15. I weigh 152, and a little chunky. I have no energy and get out of breath just talking.?

Ever since i was little, i never wanted to go outside and play with my little friends or play tag or something. i would always get short of breath and i always felt sluggish, even though i dont constantly gorge on big macs and diritoes. i eat relatively healthy now. but im now, even though i get enough sleep, drink enough water, etc, i always feel tired for no reason. i also feel dizzy and fatigued. a really crappy embarrassing thing is my breathing. whenever i even talk for a few minutes, i feel out of breath. i get out of breath constantly. im talking sitting inside with the AC on. last november i had my gall bladder removed, upon which i was diagnosed with endomitriosis and given the birth control rod to control it, which has been BAD and i am hoping to get it out soon. i have had extreme constipation problems my whole entire life. im wandering whats next. please, someone, tell me whats wrong with me, or give me a few diseases. i dont drink soda, and get over 8 hours of sleep. i want to be active and my dizziness, shortness of breath, fatigue, and nonexistent energy level prevent it. please, help.