Worried about my weight.

I’m 15 and have a height of 5’0 and my current weight is 105.5 lbs. I use to weight 115 and never had a problem with my weight but then suddenly my family kind of pressured me to lose weight for a photo shoot that I had. I started working out but only to get toned I didn’t want to lose weight. But slowly and slowly I started watching what I ate and sometimes I would go days without eating. There was a time when I felt like I was developing an eating disorder and even my English teacher spoke to me about it. After the photo shoot, I started eating again. At that time I was 109 lbs but everyday the numbers would just go down and down no matter how much I ate. It’s still like that right now and I’m so stressed because I don’t know what’s going on.