what exactly is healthy?

ok this can be a bit of a touchy subject not for me but for others...well I've always had a up and down weight thing going on for a while well mostly through middle school when your body starts to change in ways you didn't know that it could...during middle school I was say I was chubby just a little extra baggage not too much, but latley I feel like I've got super thin way skinnier than ever before..and I do not like it so I was wondering if anyone knew where is the happy medium between being fat or skinny. You can be fat and become skinny and still not be happy with yourself. With that being said just love yourself and try to stay happy..I d/k I think my body is just changing but its weird..I wear a size 7-9 in bottoms like jeans shorts etc. but all of sudden I can fit a size 3 wow I really didn;t see that one coming it was a complete shock. Even though my body is changing it hasn't changed me into a person I know I'm not...its not like I'm over eating or making myself not eat..I d/k what it is but no matter how my body is I've learned to be comfortable in my own skin because at the end of the day its you that you have to face...xoxo Jasmine