We are extremely confused about weight and health as a culture. No--thin isn't always healthy but Yes, fat is usually unhealthy.! Sorry, not sorry.
I am like you--i've been size 14 and am now a size 4. I got here by focusing on health and I feel much better. I'm not fat shaming anyone by saying that I am much, much healthier. It's not because I'm thin, but losing weight came with the package of regaining health.
Humans were meant to be slender, like all other animals (except those that hibernate, who are temporarily fat). Putting on extra weight could come from a rare thyroid disorder or being jailed on a fat farm (as in a miniscule number of oppressed African women) but it USUALLY comes from an unhealthy metabolism careerning toward heart disease, diabetes, and other health problems.