Negative things and positive co-exist together throughout our lives. It's up to ourselves to choose which ones we want to see. I often experience crippling depression and happen to have just acquired four budgies. They interrupt my negativity in positive ways. If you are alone and have nothing to care about, find something to care about.... be it others in some capacity, or in looking after some other living thing. Immerse yourself in their needs, or elsewhere, where there is the possibility of reciprocation. Negative past experiences, for instance, need positive new experiences to push them away into insignificance.