i think 2 weeks is too early to decide if you hate something or not. What exactly do you hate? is it something that can be fixed? It probably depends on your store but if you tried to step down after two weeks of being a tl at my store/district you would be let go.
It's better to make your feelings known now instead of investing a lot of time there and then stepping down. More than likely they will want you to stick it out for a bit (the probationary period), but if it doesn't work it just doesn't work. You tried, the role isn't a good fit for you. They obviously have faith in you or you wouldn't have been promoted. It's not a bad thing on you or them if it's not a good fit for you, as long as you are upfront with them from the beginning. Explain what you like or don't like, give the reasons, be willing to work with them.
With that being said, if you step down then you can pretty much forget about any future promotions.
It can be too early to tell maybe. 2 weeks would for me. Try and get to know your team and make your job fun (is this possible? Lol) in one way or another. Redand is gstl if you have gstl specific questions.
I hated GSA. It was either boring or OMFG I HATE PEOPLE!!@ewdsa!!!! Very rarely was it a good medium. Not what I want for 8 hours a day. Everyone is different, but in your case it sounds like it's not going to get any better. I don't want to be the pessimist, but since you've already received the optimist responses - it's perfectly fine to step down. You'll more than likely piss your superiors off, and you probably won't get another chance at another promotion, but screw them. It's your job. You shouldn't go home miserable every shift. It's not worth it.
Jmho, it takes awhile to find yourself in a tl role.... You do not get to pick your role, even if there is only one opening, they may move someone else to get what they view as the best person for the job. My store had hinted at one position for me, then it became something completely different then a move to the original option several months later. Looking back my store made the right choice.
As far as gstl, ive done it some, it forces you to grow a backbone and be orgainized. Think about how others have done your position, rely on your fellow tls for advice & help.