A friend is feelng sad, hurting emotionally, lonely, hungry yet doesn't feel like eating, has a bad headache, and having crying spells. It started this morning. What should I do?
This morning? It sounds like something has happened which upset your friend a lot. Often relationship breakups, deaths, job loss, and various other events can precipitate painful reactions like you describe. Ask your friend to share with you what's hurting, if s/he can. Your presence may help. If these feelings continue for more than 2 weeks, your friend needs a doctor; if suicidal, needs this care now.
See psychiatrist. Your friend is showing signs of depression, she needs professional help.