Lack of confidence

I have a serious lack of confidence I was very small my entire life and once I had my son at 15 (yes I know that’s very young) I got really big.

Now I’m 18 and still haven’t been able to really lose the weight, my boobs went from being cute and small to freaking saggy size Ds and I went from being 125 pounds to 150. Plus it didn’t help that my ex constantly put me down, called me fat, made fun of how I dressed, even told me about these other girls who were better than me, so I quit trying to look good and now wear nothing but giant shirts and leggings, I feel ugly and disgusting. Every time I try to dress nice my body doesn’t look right in what I try to wear, I look like a fat whale in everything. I’ve let myself go so bad. I just wish I had confidence, I just wish I could be like other girls my age and wear anything and not care what others think or point out everything that wrong about me in my mirror.