You will feel strong and happy to the degree you feel your actions have some meaning. Life includes a good deal of suffering in one form or another. If the suffering has some meaning, you can tolerate it well and even find happiness while suffering. Viktor Frankl discovered this while he was in one of Hitler's concentration camps.
Choose something you're unhappy about. Now ask yourself: Is there some greater purpose or meaning that is being paid for by my suffering? It doesn't matter what anyone else thinks or what they might think about it. What matters is that your life and your struggles have meaning to you. Does it serve some greater end? Is your suffering the price you must pay for some important purpose?
Don't come up with an answer right away. Ponder it, like a Zen koan, for days or even weeks.
Read more: Meanings And Feelings
and Master The Art Of Making Meaning