Paediatric relationships

I have recently completed my paediatric placement in a hospital on the oncology ward that involved working in both impatient and outpatient setting. The most challenging aspect of this placement was determining the appropriate level of emotional involvement with each patient. As children in this setting generally receive treatment from this department for extended periods of time, both as acute inpatients then ongoing outpatients, they see many allied health staff over their duration of care. I learned that when working with children, it is important to establish their trust and build a friendly relationship with them in order to get compliance with their exercises. On the other hand, I found that once they have your trust it is difficult to not get too emotionally involved. As children need a level of stability in their lives, if they are continually building relationships with hospital staff that are then dissolved once that staff has been rotated it can lead to constant disappointment.
There was one patient on the ward that I found particularly difficult to limit my emotional involvement with - a teenage girl that was diagnosed with an osteogenic sarcoma in her distal femur resulting in an above the knee amputation. Over my four-week placement, she was constantly in between the hospital for chemotherapy and at home recovering. While in hospital, physiotherapy treatment included gait re-training with her prosthesis on the ward. During these sessions, we built a strong relationship based on similarities of interests. At the end of my placement, I found it difficult to notify her that I was leaving, as she was asking me to be her friend on face book and planning to tell me all about an event she was going to on the weekend the next week.
From a professional point of view, I know it is inappropriate to give out any contact details including facebook, and from a personal point of view I didn’t want to delay the goodbye till the very end because it was easier for me to just say goodbye and leave without having to deal with the repercussions. So I decided to notify her on the Thursday that I would be ending my placement on the Friday and was unable to exchange any details due to confidentiality reasons. I was met with some resentment on her behalf and frustration and on Friday she refused to see me. I found this experience very difficult and wonder if I became to emotionally involved at the expense of the patient. If anyone has any comments or ideas on how this situation could have been handled better that would be much appreciated as I do intend on working in the paediatric setting again following gradation and don’t want to repeat this incident if possible. Thankyou.