Yes! And yes, you are right to freak out. Btw, the movie is called Avengers: End Game.
Although the trailer is a bit vague, it does provide some idea about the aftermath of the Avengers: Infinity War.
The trailer begins with Tony Stark, recording, what appears to be his last message to Pepper Potts. Tony's stuck in a spaceship with no food and water and the oxygen is almost running out.
Captain America and Black Widow are meanwhile, at the Avengers base, mourning along with Bruce Banner.
Although they do seem to have a plan and Captain believes in it like his life depends on it. Thor also briefly appears in the trailer, possibly mourning the death of half the universe.
Thanos, meanwhile has given up wars, as you can see his suit of armour put at rest in a farm he now lives at.
But here's the one thing that should really get you hyped, it nothing has till now. Jeremy Renner is back, as the Ronin.
And Ant-Man's back too and at the gates of the Avengers base.
You can watch the trailer here:
So yeah, get hyped. Half the universe is dead and our heroes are on a mission to change that. If the last film proved anything, it's that Avengers: End Game is going to be one hell of a ride.