Beak worries

Hi everyone, I’m new here and I’m really looking for some advice, I’ve had Harley for around 6 months, she was a gift from my dad who got her from a pet shop, he was told she was around 14-16 weeks old.
Harley was really nervous but quickly learned to step up and wolf whistle. She would only eat seed and was very timid.
I had had her two weeks when she suddenly seemed really withdrawn, the next day I came down to find she had either blood or vomit around her beak, she was shaking and not interested in anything. We nearly lost her, the emergency vet I took her to was not hopeful, they gave her a shot of antibiotics and she did pull through but I’ve always felt she’s a bit withdrawn. ‘ Ive adopted her a friend (from a breeder) and they get along fine but my new tiel is so lively and curious in comparison’
Ive always made sure she has toys, cuttlefish, etc but she doesn’t seem interested. The top part of her beak often gets really long. But recently I’ve noted some overgrowth underneath.
Also due to not trying or eating any fruit and veggies I use vitamin drops in her water.
I can’t seem to find an avian vet in my area and the vet I take my dog to just advised me to do all the things I’m already doing. She’s eating, drinking and vocalising fine at the moment but I’m worried. We would be really grateful for any advice.