Can’t seem to keep myself motivated 😭

To makes things clear, I’m 16, 5’6 and 170 lbs. One of the things I’m most conscious about is my body 😔 I’ve noticed since last year, I’ve gained 30 pounds like wtf? I didn’t even notice until I stepped on the scale and thought my scale was broken, so I bought a new digital one. But it ended up being the same weight lmao. Since then, I came to the realization that I really need to lose weight in order to maintain healthy body but my problem is I can’t find any motivation. It’s really hard especially when people are promoting body positivity and to be happy with yourself. Sometimes those things really do get to me and I start feeling myself but then it hits me again when I wear clothes that don’t even fit me anymore. To be honest even last year when I was 139 lbs, I thought I was overweight and wanted to lose some but once again, I always lost that motivation. So basically, how in the world do I find that motivation to lose weight with all these distractions? And any tips and tricks on how to lose weight in a healthy & effective way?