Too early to quit?

Can I resign part-way through my training contract as I think I’ve made a huge mistake.

I started my training contract this year but I am really hating it and feel I have made a big mistake. However, my law firm sponsored my GDL and LPC, and I’m worried that if I resign I will have to pay back this money. I can’t seem to find the answer to this in my contract and I am scared about raising it with anyone at the firm. What should I do?