I hate the double standard in fashion so much. A skinny person wears a graphic t shirt and jeans/shorts and they're called stylishly casual. I do it and I feel like a lazy slob who can't be bothered to dress myself nicely. Fat people get criticized and called gross for wearing casual clothing but skinny people get compliments. I hate this.
This is a very prevalent issue for many, so at least you're not alone (if that can be comforting).
I do believe the internet is to blame somewhat, you get bombarded with beautiful bombshells and ""perfect"" bodies achieved via photo editing programs. Even on Tumblr, the bodies you typically see are taken with fashionable outfits, with good lighting and poses, quippy captions and fun backgrounds. This isn't a knock on Tumblr Fatshion blogs, but always keep in mind how staged it all is.
Fatphobia in fashion is a big big BIG problem, within communities and the overall industry, esp as a fat woman/femme. You're absolutely right, skinny folks get lauded as fashionistas in ugly outfits and fat folks are ignored. Even looking at the notes between skinny fashion and fat fashion shows the disparity; fatshion blogs receive a pitiful amount of likes and even less reblogs (for high caliber posts) compared to mediocre skinny fashion posts.
A fun thing to watch, if you're feeling up to it, are those 'Is it Skinny or Fashion' videos, or other humorous videos!! I love watching YT for some fatshion and fat positivity, off the top of my head Sierra Schultzzie is amazing, Sarah Rae Vargas is wonderful, Carrie Dayton is fun (anyone feel free to rec their own favourites!!)
Also, I know this is hard, but please try and forget others opinions on you and your outfits!!! People that always have something negative to say aren't people you want to associate with!! I used to flat out tell my coworkers it would be a cold day in hell before I'd come to them w fashion advice, obv this won't work for every occasion but always remember you don't have to put up w negative comments about your appearance/body.
I hope this helps!! The best advice is to surround yourself with wonderful fat folks if possible and to not take any shit <3