Yes some people are natural healers and they usually do get bombarded with negative energies when they start to use their healing power. I'm sure that mental issues are people being attacked by negative energies, it really is enough to make anyone act crazy, constant voices in your head etc.
It does take awareness, knowledge and some good tools or methods, done regularly to keep our energy clear. So pleased you've found ways to deal with this and feel happy and radiant! :)