My 7 month old used to sleep for 3 1/2 to 4 hours a day but recently he has only been sleeping for 1 hour 45 minutes to 2 hours during the day and I don't no why he won't go back to sleep after he has woken up either what can I do about it to help him sleep for longer like he doesn't get irritable or anything but shouldn't he be sleeping for longer than that he goes to bed at 8 and wakes up at about 6