People of God in Scripture had such parties themselves. I think of Elijah and Jeremiah. God picked them up as well, and helped them to continue on in faith, and in service for God to the people.
There are dangers when one is down. We should always keep a close watch on what we say, and it's particularly important during these times that we keep our mouths shut, and that we be careful not to express ourselves nonverbally, either, in regard to any grievances we may have. We've all stumbled in this regard. But we can learn and by grace do better.
But most of all, we need God's grace to lift us out of that, and into his grace and love, the truth as it is in Jesus. To try to work with God in this life is not easy, either in regard to ourselves, or in seeking to help others. We do well to seek to major on prayer and on being quiet (the quiet is important in my case, since I tend to have plenty to say most of the time). And I do well during such times to keep busy, which just before God broke through to me yesterday, was precisley what I was able to do.
Of course much more can be said on self-pity. I've just touched on it a little, from my experience yesterday. What would you like to add on it?