Lately I've been trying to talk to myself a lot more. It's something that both Doug Wilson (in the sermon last Sunday) and then Nancy Wilson (in the Bible study Wednesday) have been shoving at me, and finally, it came through. God just had to re-send it.
What am I talking about? Well, when things are rough, we usually do one of two things: we either talk to ourselves or listen to ourselves, and these two options really don'y go on at the same time. Listening to oneself might sound something like one of these: I'm such a failure at this... I'll never get my assignments all done on time... Why is he so mean to me... God doesn't even care... and you get the picture. This is what our fallen hearts do to us all the time- maximizing our trials and troubles so that all we do is drag ourselves down into the mire of self-pity or doubt or bitterness.
Talking to oneself is more like: Look at what you've made it through already!... This is all for your good... God gave this to you... He will help you... Remember to sing...
Pastor Wilson was using David as an example. You've seen those Psalms- they start with depression, Where are You, Lord? and end with, The Lord will deliver. David starts to tell himself what he knows is true, instead of doubting.
It is true that you can change your own mood.