Hi pebbles,
Take heart; everything is possible.
Recently a good friend of our family got to the finals of "Australia You've Got Talent". He sang in the style of Frank Sinatra, and was coached by some middle weight Sydney vocal trainers. Well to make a long story short, he is now booked out for the next 18 months. But since the end of the show, his new manager, has ensured he gets the best training available.
During the show, singing that 'Sinatra' style (grovel type) he was only able to sing, including practice no more than 2 hours before his voice started to show strain. With his new trainers, he can sing including practice in excess of 3 hours without any form of strain. And he said he can go much longer than that. He now just has to practice this technique to extend his vocal range and strength.
I don't understand vocal training myself, however to those who know the mechanics of it, can perform wonders. Obviously you have to seek out the 'top shelf' of the industry, but it certainly worth it.
Keep up the great work, and be safe, well and happy
Lotsa luv
Catherine