Я не мог(ла) выкинуть из головы то, что она мне сказала.

Смотрите: 

http://dictionary.reverso.net/english-russian/get%20it%20out%20of%20my%20mind

http://context.reverso.net/translation/english-russian/get+it+out+of+my+mind

Here is another way to write the sentence so that it is more understandable:

“I couldn't get out of my mind what she told me.”

It means that “I could not forget what “she” told me.”

I hope that helps.