連日ワールドカップを見て寝不足だよ。って英語でなんて言うの？

To explain that you didn't get a lot of sleep because you are watching the World Cup matches, you can say "I haven't slept much because I been up late watching the World Cup."

When you want to explain that you have not been sleeping too well because you spend your nights watching the world cup; then you may explain it in the following ways:
-I haven't been getting much sleep because I have been watching the world cup every night.
-I spend most of my nights watching the world cup. This is why I am not getting much sleep

If you want to explain you haven't had much sleep you can say 'I've not had much sleep' or 'I haven't slept much' both meaning the same thing
By explaining why you haven't slept much then you would say 'I have been watching the World Cup every night'

Well, some things are more important than sleep and if you are a football fan, obviously you will want to enjoy all the live action.

The two sentences you see provided above are terrific ways to express to your listener that you have not been getting a lot of sleep because you have been watching the world cup. In the first sentence you will see the term shut eye and in the second sentence you will see the term hit the hay. Both of these terms mean to sleep. These terms are appropriate for informal settings.

1. I have given up sleep to watch the world cup.
   私はワールドカップを見るために眠りを断った。
   This statement means that you have sacrificed your sleep in order to see the world cup.

   2. I can't sleep while the world cup is going on.
      私はワールドカップが起こっている間は眠れない。
      This statment means that for some reason while the world cup is going on, you are unable to sleep.
      The reason could be excitement over the games, or maybe the noise that your roommates are making during the matches.