You are still growing, most of the men in my life continued growing until the age of 20. You still have time 5'9" - 5'10" is considered average nowadays. So you are at the least almost there
Don't worry. 5'8" is actually pretty tall for your age, believe it or not.
Men typically grow until age 20 - 21. At your rate, you could easily be 5'10 or taller. My brother was around 5'9 at your age and he was 6'4 by the time he was 20.
BTW, there is no natural way to increase your height... only time will tell.
That's the same height as me, and I'm a girl. And I'm like, 2 years older then you. I'm shure you'll get taller, if not, that's okay, because 5'8 is still considered tallish... And you might not be done growing yet.