I have offered this phrase before, but am only slowly realizing the life changing potential of treating EVERYTHING that happens as an opportunity for growth and following happiness and effectiveness.
We cannot control loss, outside of exercise of common sense and prudence, nor can we directly control our reactions. You cannot force yourself to feel anything. You feel what you feel.
But what you can do is add a cognitive filter which looks at situations in one way, and not another, and which is primed not to wail and moan only, but to see what is there that is positive and has been missed. This applies both to the situation itself, and to emotions which are latent and possible, but suppressed.
I really do think many people make themselves much weaker by assuming what they are capable of, rather than allowing their actions to do themselves. Not sure that’s the best way to put it, but allowing is a big part of my current focus for myself. I had no idea I could feel good in the morning, feel good at work, and feel good in the evening. This is not my habit, but I see it is only possible by suppressing natural corrective energies which emerge spontaneously if allowed.