constipation? Hi,

i have a 16 week old kitten, we have had her for 1 week and up to now she has been well. Last night she was laying down and crying quite a bit, her back end was tensing like she was pushing. She is eating fine and drinks boths kitten milk and water. During the night she has been walking and playing as usual and is able to jump on to the bed and settee so do not think it is her legs or back. she doesnt cry if you touch her stomach or pick her up. I have noticed she doesnt appear to have been to the toilet since saturday night even though i have heard her scrambling about in it. im really worried. this morning she was walking ok but kept laying down after a couple of minutes with her back end muscles tensing. does this sounds like constipation? any advice would help as im stressing out...

thank you Abi x