Please Read This I need help BAD!!!!!

I am a young musician and i am having a horrible time figuring out vocal melodies for my songs. I have music composed and i know i have rough lyrics written for some of them. I really need to figure out how to make up vocal melodies because this is my one hurdle in writing songs. I know i am capable of writing great songs its just i cant get over this problem of vocal melodies. ANY HELP ANYONE COULD OFFER WOULD BE GREATLY APPRIECIATED I NEED HELP SO PLEASE TAKE THE TIME IF YOU CAN.

Thank You.