All these things that I have done

Yeah I'm sure the tiredness is a factor. I've actually read stuff (New Scientist I think) demonstrating that people who are sleep deprived put on even more weight than you'd expect from the extra calories they consume - presumably from a combination of not having enough energy to be active and nebulous metabolic stuff.

On the exercise front there is a quote from exercise circles to the effect that if you are a reasonably serious gym person you will do - what - 3 hours a week? Which leaves 165 hours (or 109 less sleep) which the three in the gym cannot possibly outweigh - it has to be about lifestyle. Unfortunately quite a lot of that is down to whether you are a naturally fidgetty person, however you can still adjust your average hourly activity level, but not if you are exhausted to do so.

Have you considered redecorating the house? or doing an enormous spring clean?

I would absolutely shut Charley in the kitchen at night - she's not a tiny kitten any more and she can take it. She'll probably never be happy about it, ours certainly weren't, but as t__m__i points out, your health is at stake. For obvious reasons I'm pretty ruthless about sleep.