Should I lose more fat or gain muscle?

ZacG96

I'm 16 and I've lost about 90 pounds and I have lost muscle through my weight loss attempts. I've been dieting still for who knows how long and I was wondering if I should start gaining muscle or keep losing fat before I gain the muscle?
I still look fat with my shirt off. I don't understand why. Maybe I dot have enough muscle. I'm not sure but I really want to improve my body image cause right now I feel like I look disgusting. I run track so I'm getting plenty of cardio/exercise. What should I do?
I'm currently 6'0 at 171 pounds