Guccibabe, if DS is crying then it doesn't sound like hunger to me. I would have said it was more likely a nightmare, although it's unlikely he had on every 2 hours. Given the frequency then, my next guess would be pain. I would wait to see what happens over the next couple of nights before introducing formula. In fact, at his age, I don't think he would need formula ever. If it turns out he needs more sustenance, try increasing the solids first. At 12 months you can add cows milk to the mix as well so I would hold out until then.