Newbie needs support!!!

As being a new psych nurse (almost 2 years), I feel like the more experienced nurses are unwilling to share their knowledge about dealing with some of the patients. I keep reading and trying to find all the info I can to help myself to be a better nurse. Can you suggest any good reading for interventions?

I have been feeling anxious dealing with psychotic patients. Like my pt last night who was disruptive, running naked and urinating on the unit. Once I called security and we got her into the room for an IM, I was at a loss for words....I am trying to be therapeutic and explain our behavior expectations on the unit, but then I feel almost guilty for having to give her an injection even though clearly she needed it. Do you have any advice for a new nurse? I know I need to work on my assertiveness and confidence. I feel like the more experienced RNs can see that I get nervous and are feeding off of it. I do like working with this population of patients for the most part...I just feel intimidated by the ones who end up on our unit and seem like they belong in jail.... Thanks for any help you can give me!