See, the technical term is 'Christian Witch' but they don't like the term 'Christian Witch' so they go with the more peaceful name 'Christian Wicca'. Problem is, this is like saying 'Buddhist Muslim' or 'Jewish Hindu' they are two different religions. I'm fine if people choose to call themselves that, but it's not technically correct. [But, personal preference, so whatever]
Cleansings can get rid of negative energy. Meditation, journaling and mindfulness can help with negative thoughts. Just understand good and bad will happen, don't dwell, accept what is and move on. Many people choose to be positive all the time and ignore 'negative' emotions. Sometimes optimism is best, but bad things happen, if you feel like crying, cry, don't beat yourself up over it however. Finding the balance will help you.
You should read books on Wicca and Christianity to find the path for you, but you could just join Christian Wicca Coven and ask them for further information. Good luck to you.