I'm so sorry you're feeling this way :( 
I know what you mean about beauty having too much value placed on it for women.
If it helps, and I really hope you understand I'm not trying to be arrogant here, I'm just saying to illustrate how much our negative self perceptions are in our heads - I've been told all my life from very young that I'm pretty, but there have been many times I don't feel this way about myself.
Before I met my DP I also craved male validation, it was the only way (and sometimes is on my lower, more insecure days) I could feel properly good about myself. But you honestly do get to a point in life where you feel so different. It doesn't come on it's own though, it genuinely (and I'm aware this might sound horribly cliche and corny) really does come from self love, which breeds self confidence, which is attractive in itself.
You need to work on your own mental perception of yourself, and if it helps, make lots of effort! It really boosts my confidence to know I'm looking my best, and changes how I interact with people for the better. It is truly sad how much self worth can be placed on appearance, particularly for women, but there's no point pretending it doesn't exist.
Come on OP, get your hair done, pluck/wax/preen, treat yourself to a consultation at a makeup counter and get a new set of flattering cosmetics, update your wardrobe and just have fun with yourself. Insecurity really is a bitch, I know. But you said yourself, you turn heads already ;)