confrontation among nurses

I am a new-er RN... I've been working 2nd shift on a general med-surg unit for over a year now. I am a quiet, shy person who has almost always gotten along with everyone. Since starting on this unit, I have found that I get along with everyone at work as well. I go out of my way to help the nurses I'm working with (because I know what it's like to work with someone who isn't helpful and I don't want to be that person). Today, I worked with an older nurse who I've always enjoyed working with. We help each other. After working in a management position for home hospice for a few years, she's returned to working the floor. She's per-diem staff (meaning she only works a few days a month) but has been working on the floor for longer than me, a little over 5 years now. It's surprised me to find that she's always asking ME questions. Usually people don't ask me, since I'm new. Today, for example, she asked me to hang an IV antibiotic for her because she was "nervous" to do it in front of the pt's daughter who was a nurse.. I know what it's like to not know how to do things, so I gladly did it for her. She also asked me how to write a telephone order on the computer. I calmly sat next to her and explained it to her. She also asked me how to give meds via an NG and I explained that it's similar to giving meds via a peg. She also asked me to set up suction in one of her rooms, which I gladly showed her.

I had no One Touches to get for the evening, as none of my patients were diabetic. She was at the nurse's station holding the One touch machine, and saw me walking down the hall past her. She looked at me, smiled, and said "You better help me with these." I assumed she was joking and laughed it off...she knew none of my patients had one touches ordered and I was behind after a patient to ICU early in the shift. I sat down and began to talk to the secretary about the fact that it was irritating that first shift hadn't given half of their meds, and left them for the per-diem nurse to give. the secretary told me I should write 1st shift up. i looked at the per-diem nurse (who was still in the process of turning on the one touch machine) and said something like "well it's your patient so you could write 1st shift up if you wanted to, but I'm not going to. I don't even have time to write someone up." the per diem nurse went on to yell at me. she said that she is sick of my childish behavior, saying that it was wrong for me to "pull her into this childish game" then she said "and you haven't even helped me with my one touches". I apologized that she thought I was acting childishly, gave her a hug, and got two of her four One touches. And things seem to be back to normal between us...

She's a well liked nurse and I've never seen her have an issue with any other nurse, so I'm sort of trying to evaluate what I did wrong in this situation. Is this kind of be-littling something that commonly happens among nurses under pressure that I just haven't experienced until now? Or should I learn from this and make some changes. To be honest, I'm embarrassed. I get along with *everyone* and I find it kind of odd that my first confrontation with another nurse happens to be with one of the nicest nurses on our unit. I'm thinking that maybe there is something I'm not seeing. Perhaps several of my co-workers find my actions childish and are just all too nice to tell me... perhaps she was the only one with enough nerve to say it to my face? Any suggestions? I guess maybe I just needed to vent. Thanks for listening...