Your instructor saw traits in you that she felt would make you a great fit in an ICU. Most instructors will discourage new grads from the ICU so first pat yourself on the back. Good work! She probably saw that you are detail oriented, teachable, and react well in high-stress situations. These are the 3 traits any beginner ICU nurse must have. Everything else can be learned.
Take the critical care course at your hospital combined with AACN's ECCO course (if provided).
Purchase an Essentials of Critical Care nursing book (I think that's what it's called)- published by AACN and study this after your Ecco course is complete.
After every shift on orientation take your patient
diagnosis and search for CE's on AACN's website and read about it and take the post test.
Enjoy your days off and truly distress. Find a friend you can vent with outside of work because it can become overwhelming.
Always believe in yourself. Stay humble. Always ask questions. If you don't know how to do something, say so. Remember, you're there for the patients so try not to focus on the politics of nursing so much. Do the best you can. The first year will be extremely challenging but ICU will always provide a good challenge. Stay teachable throughout your career and always follow best practice and standard of care regardless of what everyone else on the unit does!
Keep up the good work and welcome to the club