Take time to examine the current relationships you have that are positive, encouraging and healthy vs. relationships that have negative associations. Think of the image of Superman and Kryptonite as a metaphor.

Who or what experiences strengthen or weaken you? My strategy is to examine those relationships that you initiate, look forward to, enjoy and then feel great afterward. Then look at those that cause your stomach to churn and feel draining and distressing before, during and after. 
The message... pursue those that enliven you, avoid those that deaden. With the right company, you will feel supported to become the best version of yourself!