Dd is 2.5 and has recently become increasingly lethargic. She now falls asleep a couple of hours after waking and whenever we go anywhere in the car (she dropped naps ages ago). She hasn't been obviously ill or had temps. She's not as bothered about eating as she was either. She can have good phases - able to play/dance/run about and seems happy, but then will curl up and sleep.
GP thinks viral but it has gone on for a while now.