history: I am starting a new job soon. It is quite a step up from my current position, so I'm a little scared that I won't perform well.  I recently got a promotion. It's quite a big step up from my current role_comma_ so I'm very nervous that I won't do well in it.  That is great news. I think you just might be nervous. They wouldn't have promoted you if you couldn't do it.
current: I hope so, everyone tells me I'll do great, but I still have some reservations about it. It's way different than what I do now. I've not been sleeping well. 
next: Well usually when you think the worst it turns out to be okay. I think you should try and relax.