You may not believe this, but there are disadvantages to being attractive too. In the workplace you can be seen as a bit “soft” or not serious enough. You mention struggling with friendships - this can be extremely difficult for attractive people too, as people can be so bitchy if you trigger their jealousy. They can see you as “competition”, no matter what you do or don’t do, or project their insecurities onto you.
I say this, not to invalidate your experience, but more so to provide perspective.
Anyway, what I will say about your friends is that they don’t sound like particularly nice people, I’m afraid! I do concede certain things may be easier for conventionally attractive people, but life shouldn’t be as difficult as you say it is based on this alone and I do suspect that you’ve not been surrounded by the “right” people.
In terms of your self-image, could you try a makeover? Do you apply makeup? You can contact makeup counters and ask for their help - they can book you in to both match you with products and show you how to use them properly. Less is more. Tame the mane regularly if you’re not already and don’t just throw it up/leave it to its own devices every day. Whether that’s achieved via products or heat tools will depend on your hair type and how you want it to look. Consistency is key to looking out together. Watch YouTube tutorials specific to your hair type and your goals.
A good skincare and oral care routine is a must, too. Again, less is more with skincare. Theres so much on the market but honestly I just love the brand ‘Simple’ - a good twice daily cleanser, moisturiser and an SPF for under makeup will do the trick. Get a good electric toothbrush and book regular dental check ups if you’re not already, and maybe invest in either Invisalign or a whitening course if either of those things would work for you. Also so important to move and nourish your body with the right foods.
You say you have hobbies. Lean into these even more - you can meet people through your hobbies whereby your connection will be more than surface deep. And hey, perhaps your current friends are actually threatened by your personality, wit, talents, etc etc… who knows? Their “looks” may be all they have…
Most importantly, you are NOT worthless!! Good luck!