Is my Momma cat in labour?

This morning our cat Misty seems to be showing signs that she will be having her kittens soon. Can anyone tell me some specific signs that would confirm this. We have her locked in the bathroom where here birthing box is. She has been meowing way more than usual, she is generally not very vocal. And hasn't slept much, if at all this morning. Any signs anyone could give me, would be greatly appriciated.
Thanks! ABK

Nevermind she is definitly in labour. I'll keep you posted.

Our cat had hers last night,she did not howl or moan she stayed in one spot,We had her box in my daughters room,But she decided she was having them in our closet so i left her be,So we moved the box to the closet i found she just layed on her side,Then you could see he push then within 2 monutes we had a baby it really is facinating watching new life brought into this world,Her first baby was born at 8:13pm 2nd,9:29,3rd 11:30,4th 11:53,You see the stretch i was exaused lol and i never did any work,other than clean there noses mama was more into the afterbirth at the time.Good Luck!

We had to assist more with the two that were breech cause Misty had a harder time with those two. The third was head first and Misty had no trouble with that one. All I had to do was wipe the face off of that one. She did an awesome job and is being a good mom. We are really proud of her!