I'm going to scream soon.
Why are you going to scream?
I have not obtained a ticket for a concert.
Well, you better get on it then, if you want to go. There is no way to get in without the purchase of a concert ticket.
I'm going to scream like I'm at the concert.
It sucks that you're having trouble getting tickets to the concert. If you end up not being able to get one, you shouldn't scream. While it's understandably upsetting, you should get a better handle on your emotions.