I totally understand what you are going through! My girls were 1 and 3 when I was diagnosised. They are now 6 and almost 8.
Don't worry about the kids, they will adjust. I would ask your older ones to help with the younger. They are old enough to get them snacks, drinks, help with diapers, pick up toys, bring the clothes to you from the dryer so you can fold them...those sort of things. I never complained in front of the kids...if they would ask, I would just tell them that I wasn't feeling well. If they ask me to play with them, I would have them bring a book, or coloring, or a toy over to the couch and we would play that way. You and your family will have to find a new "normal" that works for you. Since you both work, then your husband is going to have to pick up some of the slack at home to help you out at least until you find a med. that works for you.
I was so sick that we had to move in with my parents for a few months, so my mom could basically do everything for me and my family. Then when I was able to move back home, we hired someone to come in and clean the house every week. Then as I got stronger it was every other week, and then eventually I was able to do it all myself once again. Don't be afraid to ask for help. That was hard for me at first...but I eventually realized that friends and family are more than happy to help out, but they just don't know exactly what to do for you...so ask them to do whatever you need.
Remicade gave me my life back! This Dec. will be 4 years since I started. I now do everything I want to do! Every once in a great while I while have a day where I just have to slow down, but that is just a reminder that yes, I still do have a disease, but you adjust, and keep living life to the fullest! Hang in there! It will get better, and your kids will be better and stronger because of you.