Nursing school is equal parts learning how to be a nurse and learning how to be a nursing student. Nursing school requires a different approach than, say, a mathematics major. No calculus professor would ever dock you for nor being their kind of personable... a clinical instructor might. Whereas other fields only care if you know the material, nurses care how you show that you know the material. It's frustrating. You'll get through it.
For forgetfullness, come up with a way to better retrieve knowledge. Meet with the professor to discuss your strategy. By seeing you use it, hopefully she see you care. Also through continued interactions, she'll warm up to your way of expressing yourself.
However, I will say it doesn't really matter if you're not outgoing. The best professor I had told me that nurses need all types because we take care of all types. As you work, you will find it to be true. The most outgoing nurse may click with some, while a more reserved nurse clicks with amother patient.
Anyway, chin up!