I don't know if you're anything like me, but there are those days when I feel incredibly pumped up about what God is doing in my life and the calling He has for me and then there are those days when I can't seem to get excited about anything. Can you relate? 
I mean I would consider myself a pretty passionate person, but I don't always just jump out of bed with new excitement, ready to take on everything life decides to throw my way. Sometimes, I just want to get some chocolate, curl up under a blanket and get lost in my book obsession. But our lives are about more than just feelings and your heart is too vital and too precious to let anything creep it's way in. 
Our passion in life is as unique as we are and is directly connected to our individual callings and destiny. So it makes sense that the enemy would want to attack your passion, slow you down or get you completely off track. It says in Proverbs to above all else, guard your heart, for everything you do flows from it. (4:23)