Hi, my 15 week old has been sleeping really well at night 9-6ish since he was 7 weeks but last few nights he has started waking at 2.30am and crying until i pick him up, then he wants holding and cries if i put him back down. not sure if i should be doing this or leaving him hoping he goes back 2 sleep? He is dribbling lots and putting hands in mouth lots- wondering if he could be teething already and wakes up as it hurts? advice would be great, thanks