I also feel my DH has put up with a lot from me over the years he has stayed with me and he has done a lot for me.
A while back it seemed he was at the end of his tether of listening to me endlessly go on about my depression (haven't got it anymore) and family issues. People who had done crap things (family) were getting more of my attention (my thoughts and the amount I talked to DH about them) than DH who had done nothing crap! I think he wanted me to spend some time with him where I was just thinking about enjoying being together and nothing else.
I decided to give him a break from my negative issues and use other people to talk to about those things instead of him (it helped when I got a therapist who I could talk to). I also think women are much better at talking/listening about this type of thing than men.
I focussed on making my time with my DH and DCs enjoyable and fun and focussing on them and why I love being with them. Almost immediately I could 'feel' that DH was happier!
Lately I've been ranting on at him a bit because I've got myself stressed over a few things and realised I was taking it out on him (and probably on the kids too). I was thinking about what DH and the kids want from me and realised that doing a hundred household chores wasn't going to make them happy if I was moody with them the whole time. What they really want is for me to make them feel loved. So I had a think about what makes them feel loved.
The kids feel loved if I am willing to stop in the middle of my 'chores' and listen to them properly and help them with what they are doing and spend some time with them where I am focussed on them. It doesn't have to be a mega activity, just talking to them about what they are drawing will do!
DH feels loved if I do a minimum of housework (just the things he notices because if they aren't done the house looks very bad) - dishwasher, enough laundry to have clean clothes ready in the cupboards, a bit of tidying, other stuff only when it is obvious even to a man that it needs doing! Otherwise he feels he does all the money earning but I don't even have the house in a reasonable state for him to come home and relax in. He feels loved if I cook him a proper meal (this is how he feels his mother showed she loved his father so it has stuck with him). He feels loved if I iron him a shirt ready for the next day. He feels loved if I spend time with him without the laptop on my lap doing MN or Facebook! If I spend time with him and don't go on about negative things and I have a bit of a laugh with him it makes him really happy. These things are all it takes for him and I reckon most blokes are pretty 'basic'!
Doing the minimum chores is really important I think, and doing the chores that are going to make DH and DCs feel the most loved first and just leaving things there aren't time to do. If you feel overloaded you haven't got resources left to give to your family. If you aren't thinking "I can't stop to listen to the DCs because I've got to do this, then this, then this etc" then you can relax enough to keep stopping and giving them bits of your time. They will be happier and behave better, you will be happier, and you will be less inclined to rant at your DH when he gets home! I think DHs really appreciate it if you don't give them a rundown on all that has gone wrong that day and how bad the children have been as soon as they walk in rather than showing that you are happy to see them (not just as someone to take over from you with the kids).
Sorry my posts are so long.
NAB I think you are being really strong with some of your positive thoughts at the moment and going to the Dr etc. I know how hard it can be but you definitely seem like you are making beginnings in climbing out from a difficult place! I hope we can encourage you on MN!