OP, I am sorry you are going through such a tough time. But you do sound very clear and purposeful about what you aren;t happy with in life and that is a strong position to be in, to change it.
It's brilliant that you are still in touch with your old boss and that there may be work for you there. This is proof that you are competent and likeable.
If I'm honest,. I think life will be easier for you if you do a bit of work on yourself. That's not the same as saying there's something wrong with you or that you should be more 'normal' (whatever that is) but that certain things make life easier for us, so why not adopt them early on.
If you hate your voice, you can go to a voice coach. Try one who works with actors. They will help you modulate your voice and gain control over it.
You can improve your looks - anyone can (though I really doubt you are as 'weird' looking as you say. Go for a good haircut that stops your hair from being lank - maybe shorter and feathered so it doesn't hang down. You can accentuate your lips with a bit of neutral coloured pencil around the outer edge of the lip line, filled in with same colour lipstick and a bit of gloss. Nothing much, just to balance out your features. (I have very thin lips too.)
Being flat chested is a godsend for certain styles of clothes. Make the most of it.
Finally, decide how to respond to the teasing that upsets you. You can either choose not to care and believe people mean no harm, so laugh it off, or you can speak up and say, 'I'm sure you mean no harm and you're joking but I'm sensitive about my voice so can you please stop commenting and mimicking me.' If they are half decent they will.