Give yourself some time. What's important, at least, is that you're expressing something, that the act of composing isn't something that is abstract or purely intellectual for you. Maybe improvisation will help you out. Try to depict your moods through your playing, and maybe you'll find a seed for a composition that way. Or just start playing chords, and find a series of four to eight chords that expresses something other than agony and despair! Then use those chords as a ground for melody and development.
Another way to approach it is to simply play works by other composers. Pick a mood, and then pick a piece that reflects that mood. Get it under your fingers, and then play it, feeling the mood intimately. Then ask yourself what the composer is doing to achieve that mood. What sort of harmonies is she/he deploying? What sort of structure do the melodies have? And then think about what you would do with similar structure--instead of the chord progression going here, what if it goes there instead? What if the melody was faster, or in a different rhythm? While I'm not telling you to copy another composer's works, there are always ideas that can be developed from other works, and this way you can look at the nuts and bolts of something that you know works, and use that knowledge to apply to your own work.