My Dad is a minister and often talks about an attitude of gratitude.
I love that concept. It is so easy to get bogged down by all the crap life dishes out, but the power of a grateful heart can beat all.
I really encourage you, if you can find it in you, on those days you are really struggling, take a moment to say thank you. It can be the smallest thing. Sometimes I start with being grateful I have 10 fingers to type with.
It's amazing though, how once you get started you realize that there are SO many things to be grateful for and all the annoying things that are bugging you, suddenly lose their impact and importance.
I'm not saying there isn't time in our lives to mourn, feel justified anger and be able to vent if we need to. There is and sometimes it's important to be able to feel and do those things.
I'm simply saying that an attitude of gratitude can work wonders on a really off day :)
"So then, just as you received Christ Jesus as Lord, continue to live your lives in him, rooted and built up in him, strengthened in the faith as you were taught, and overflowing with thankfulness." Colossians 2:6-7