IF I DONT HAVE A FAST METABOLISM SHOULD I GIVE UP?

I try so hard to lose weight and its not like i eat alot either hell i dont even enjoy eating anymore cause i weigh myself every nite for example one night i'll weigh 200 next ill weight 205 or 207 and its after i have a bowel movement i also did weight training for a year and a half and im bulk enough to squat 300 pounds i just dont get it i take vitamins (omega-3, b-12, vitamin c, centrum multivitamin and so on) i workout every day i barely eat and when i do eat its vegetables or lean meats especially salmon if this helps all my fam is overweight but that shouldnt stop me from losing weight am i just unlucky is there any hope for me im miserable btw im 15 5"9' o and i work out vigorously on a elliptical in the morning at ramp 6 and work my way down to ramp 1 for 25 to 30 mins a day