Urgh, I know that feel OP. I'm fat too, and I don't understand these people that condemn using the word at all. I see myself as fat, I am fat, it is fact.
While it is generally negative because being fat is unhealthy, it's not like I'm being self-loathing saying "I'm disgustingly fat I'm a pig".

Being overweight is a situation where people tell you, "oh you look fine just that way you are!" but you don't have to listen to them if that's not how you feel. If you want to acknowledge you are fat, and you want to acknowledge you want to improve your health by losing weight, people against fat-shaming should support that.