M.P.
Two things you mention ring a bell with me- one is that he is unhappy a lot, and two, he's a picky eater. Have you considered food allergies? My son has them, and his first year of life was full of crying. He was very colicky at 3 weeks and it just seemed to never end. We finally had him allergy tested after a bad reaction to egg, and found that he had a severe allergy to egg, peanut, and some other foods. We eliminated those foods completely, and he was a completely different baby. Those foods were completely upsetting his stomach. I felt horrible about it too! I felt like I should have picked up on it way before I did. He still remains a picky eater at 5 years old, but he's getting better. Hope this helps.