Ya know... what I would do is:
Sit down with the kids, and your Husband. Have a family "meeting." Not to scold them or anything... but to merely e.x.p.l.a.i.n to them... that Mommy, per her Doctor... had a surgery and so she will not always be "able" to be perfect. She is healing.... and trying her best. Explain to them... just like when they have a cold... it can make people feel lousy and grumpy. Same for Mommy. So... give her time. She is OUR Mommy... and we should try our best to "help" her and understand, even Grown-ups are not always perfect. Either.
But that we are a FAMILY... and that means... HELPING each other, loving each other... giving hugs when someone is not feeling well... or just giving them space etc.
For you... as the Mommy... when you are not feeling real great... just excuse yourself if you can... and say "Mommy needs a time-out... I'm going over there... to rest... " or something like that. Then the kids AND your Husband.. will be 'cued' that you are not feeling at your best... at that moment....
When I am PMS'ing for example.... that is what I do. I don't tell my kids I am PMS'ing... I just say, I am feeling "stressed" or need time to breathe and relax. They get it.
The thing is... kids as a FAMILY... can understand... if explained to them in simple terms... that is age appropriate. So that they also realize.... that Mommy is "recovering" and her body is healing, for example.
When I had a c-section with my 2nd child... I explained to my eldest child... (who was almost 4 at the time)... that "Mommy's body has to heal... I am sore... I cannot yet do what I usually do... I need to rest sometimes, I need help... but Mommy is fine. I just have to listen to the Doctor too..." She understood.
Sometimes... kids just NEED to "know"... what is going on... so that they understand.... the bigger scheme of things... and that Mommy is not just being crazy/bitchy.... just to be crazy/bitchy. She cares a ton... but is just per her body... has to take care of herself. You can explain to them, in age-appropriate ways.... and so they don't worry about you....
That is what I would do.
Your kids do not 'hate' you... they just do not understand.... thus my suggestion for a "Family meeting" and talk with the kids.... both you and your Husband. In a loving way... but so that they understand....
And, though your Husband works a lot... when he is home... he can help... in any way. Given your situation/condition... I would think, that is not asking too much of him. It is just about caring.... for each other....
Basic caring and helping out.
A Husband's responsibility... is to take care of his Wife too and help. NO MATTER how much he works. Its life.... he is a Husband...
AND... sometimes when you need help... can you just ask someone... family/friends to come over??? To give you a respite???? That is what I would also do....
all the best,
Susan