Do you have a melody in mind? In other words, can you sing the song and have it sound like a song (as opposed to it sounding like you are reciting poetry)?
One suggestion is to forget about composing a melody line and focus on a chord progression. The circle of 5ths is very popular.http://ezinearticles.com/?Using-the-Circ...&id=1696261
The most popular is something like:
G C D repeat:
All are easy three finger chords. You can use D minor instead of D so you don't need sharps. Start on the chord in that group that seems to fit best and just rotate the three chords as you sing. Record it using your computer or cell phone and listen back. Then nudge it here and there. The result might well sound like music, with those chords and you singing.
Another suggestion is for you to post the lyrics on the forum or record yourself singing and post a link to that, and have some of us here try to write music for it. The caveat for us is to keep it very simple so you have a chance to perform it on the piano while singing.
A third suggestion is to go acapella and sing it voice only, from your heart, without piano music.