I would not encourage you to drink something with as much caffeine as is in a red bull drink. Even if you are not pregnant, too much caffeine can cause anxiety, insomnia, increased heart rate and high blood pressure. You can get addicted to caffeine and may experience withdrawal when you try to stop.
All of this can affect your baby. You can find out more about how dangerous it is by writing to the expert in obstetrics in this forum.
I suggest you stop drinking these energy drinks completely, at least while you are pregnant.