What you love is the thing or things that you naturally gravitate towards in life. The thing that you like to do even if you weren't paid to do it. It's the things that make life more pleasant and enjoyable to live. This is what you do with your heart.
What you love gives meaning and purpose to life. It's the rocket fuel to the engine of your life.
You're profession on the other hand is what you're paid to do. It's the thing you do in exchange for monetary value. It's the economic engine of your life. It's what you do with your hands or head.
That means most times what you love to do might not be the thing that you're paid to do! That's mainly because we go to school to educate our heads and not hearts.
What you're paid to do builds your career but what you're passionate about builds your life.
"Exchanging your time for only money is what ultimately devalues your time and you in general. It is exploitation of your most valuable resource" ~ Keinosuke Johan Miyanaga on Quora.
Don't misunderstand me. There's nothing wrong with what you are paid to do. We all have something that we do to put food on the table, pay the bills and have some money to have fun. Actually what you are paid to do gives you resources And a piece of mind to do what you love to do. It's a matter of allocating your time appropriately.
It's possible to keep doing what you love to do, but in most cases economic pressures of life will force you to spend more time doing what you are paid for. Happiness is finding that delicate interception between what you love and what you are paid to do.