My DS is almost 4 months and weighs over 18 lbs. He was sleeping about 8 hours, then feeding, and then sleeping another 2 hours. Over the course of the past two weeks or so, he has been waking up every 2 hours and sometimes more frequently. He always seems hungry as he does empty the breast and then falls back to sleep. Is this a signal that he's ready to start solids? If not, does anyone have any ideas as to what is going on or how I can help him to sleep a bit longer, or is this just the way it is going to be?