DD2 (19 months) has so far been quite outgoing and adventurous, but over the last couple of weeks or so she suddenly seems to be really scared of things like animals or motorbikes. She used to love dogs, but now when she sees one (even from far away) she'll start whimpering and wants to be picked up and then refuses to be put down again for ages. Same with horses, at nursery they went for a walk last week and apparently it took her an hour to calm down again after they saw a horse!
In addition, she's started crying every time I put her down to bed at night. I usually leave her a couple of minutes to see if she'll calm down, but when I go back in she's standing there in her cot with her arms outstretched to be picked up and beside herself 
. She calms down as soon as I pick her up, but then starts crying again as soon as I leave the room.
Could these two things be linked? Is there some kind of developmental thing going on around this age that suddenly makes them scared of everything?