Never seen a pup acting this way, little worried.

Tonight our 3 1/2 month old pup is moping/sulking, could teething be the cause of this?  She is eating ok. She seems to be shying way from us, sleeping in her cage when normally shes in the front room with us.
Tried to look in her mouth but she seemed to panic don't want to push it so I got a chew and kept hold of it while she was tying to get it from me while I looked in her mouth thinking she may have been chewing wood and had some stuck in her gum but cant see any thing and she eating the chew and showing no pain.

Something is upsetting her, cage door open and she not come out.

There is a fear stage they go through about 16 weeks old so it may be that, how long have you had her?

Has anything changed in the household?

My best way to deal with sore gums is get 3 old tea towels and roll them up length wise and knot them at least twice, dampen under the tap and put in the freezer, give to pup when frozen and swap when limp, I find having 3 on the go means there is always at least one fully frozen.

Thanks for you're reply. We've had her since she was 8 weeks. She's never been like this, trip to the vets if no better in the morning.

Well that was a strange one, got up this morning and she is back to her normal self. Im pleased she is but wish I new what the problem was.