I'm no doctor, but I can relay something which happened to me years ago. I found out what it was like to live with someone who had PMS at it's worst.
Thyroid can contribute, but anything in the body that's out of whack will set off the slightest emotional problems and she knows she can't take it out on the kids, but you are her partner and she will lash out at you for no reason and the next minute be fine.
PMS is a strange hormonal trap for men. We know nothing about it and can only learn about it, but don't feel it except when you get slapped from behind. My wife would actually tell me she doesn't have control when the mood strikes.
Again, I'm no doctor, but if you get the 'Baby Factory' yanked out... the playpen will still be open and it will take some time to get some bad habits out of the way, but within a year.... things will be back to normal. My wife still talks about those days like it was someone else. We still joke about it, but there was some nasty chit going on, but I still loved her and knew this wasn't her... anyway, not all the time.
Get some blood tests done and see if this could be a possibility. Hoping things like this will go away is wrong if it's lasted more than a few months. Mourning over a passed parent can cause some of it, finances can do it, but your bringing beer to a family picnic is wrong. Remember, if you want to continue being a slob and use excuses like you forgot to put your shoes away or you take shelter every time she rears up..... stand up and take your medicine. She doesn't need another kid in the family. Be there for her and stop looking at it from your side and try to understand what she might and probably is feeling and going through. Be the man of the house and keep it together. What's your problem that you have to complain about ?? She isn't well, you know it, now do something about it and help her.