Try not to take everything personally.
When friends, family or co-workers cancel plans with you, you could get upset and take it personally. The truth is things often have nothing to do with you.
People get sick, or need family or alone time, or have to work. Whatever. People have their own full lives and – sorry – you probably aren't the focus of them a lot of the time.
Or they may be suffering from depression, as well, and sometimes need to flake out whether they really want to or not.
You're probably quick to assume that the positive stuff isn't about you. Best to figure the negative stuff isn't about you, either.