DS has been walking confidently for the past six weeks. He only crawls when going up & down stairs. Yesterday, he hardly napped and, about 30mins before bedtime, kept stumbling when walking and then, if he wanted to, say, cross the room for a toy would walk about three steps, stumble & then crawl the rest of the way. I thought this was just tiredness & he'd be fine this morning but he's only really crawling today. He doesn't seem to be in pain or discomfort, if I stand him up then he can weightbear, there's no sign of anything wrong with his legs, he can wiggle his toes, kick etc. The only unusual thing is wanting to crawl rather than walk. He does seem a bit under the weather as he has a cold & cough & is more cuddly than usual so my only thought is that he's feeling a bit pathetic and it's easier to crawl than walk. Any ideas? I'm worried but it's not as if I can turn up at the GP and go "he's not walking - do something!".