I was told I need to lose weight

Yesterday I saw my grandma for the first time in 8 months. The first thing she said to me was “wow you’ve gotten big, we need to put you on a diet”. We laughed it off but it really bothered me. I’m 17 and have been struggling with my weight for almost 2 years. No matter how much I try, the weight always comes back. Recently I developed really bad eating habits. I lost my best friend a couple months ago and ever since I’ve just really struggled to eat. Some weeks I binge everyday. Some weeks I have no appetite and eat the bare minimum to stay alive. Because of that my weight has been fluctuating to the point where I’m just scared to weigh myself. Last time I did I was 159lbs which is the heaviest I’ve ever been. I’m also only 5’0. I just dont know how to lose weight the healthy way, especially now when even eating normally seems next to impossible. I’ve talked to my doctor about it but she’s not being very helpful, I genuinely don’t think she understands how much I’m actually struggling. She says the whole “just excercise and eat healthy” which I know but I just can’t do. I don’t have the motivation or energy. Plus I can’t go see her because of this whole quarantine. I just dont know what to do at this point and my grandmas one comment has sent me spiraling to the point that the only thing I can think about is how I’m overweight and need lose weight. Help :(