HELP!! Suddenly not sleeping well in crate

[Bluecatt]

When we got Magic at 12 weeks, she was sleeping in a crate, right thru the night, from the 2nd night we had her. Gradually, for the last few weeks, she has been waking up in the middle of the night, to go out to pee which is not a big deal. But putting her back in her crate was becoming a problem and she'd whine for a bit and then go back to sleep. Well that has been getting worse and worse. Now, for the last few nights, she fights when we put her in the crate and night and whines for a really long time. She'll wake up in the middle of the night and cry and cry, even if she's recently been out to pee.
I use a baby monitor so I can hear her and at times I've had to turn it off so I can get some sleep! Anyway, I don't know what's wrong, why she has regressed like this. She has done so amazing up until now with the crate, we were extremely pleased with how well she adjusted to it. I don't know what to do with her now. At 3am this morning, my husband took her (and her crate) and slept downstairs on the couch. When I went down this morning, her crate door was open and she was sleeping on the couch with him!! (So cute, but I'm thinking "oh no! ") Could it be maybe that she's outgrowing it, she needs a larger one? I don't have the measurements handy but she can still stand up and turn around in it, although she has put on 2 lbs. since we first got her. Hmmm, maybe I've answered my own question?!