My kids are hyper active and I'm getting depressed?

My elder one is 8 and little one is 3.. they both are overactive hyper kids and now I'm at a stage where I'm very depressed.. I cannot handle them anymore.. I am absolutely sure they have ADHD but I dont want to take them to the psychiatrist and dont want to put them on medications. I am a part time working mom and they both drain out all of my energy and patience. I've seen all of my friends and relatives kids and no one is like my kids.. my husband is also tired handling them.. they cannot sit still even for one second.. they go for karate class and other class but inspite of that they say they're bored and they keep on talking and talking and I dont know what to do. even if i buy them coloring books or activity books, they dont do it alone. They always want either me or my husband to do everything with them.. We give them enough attention but they never give us even a minute of spare time except when they sleep at nights.. I've started getting too depressed because of this and have started getting very angry on them and yelling them. But it still doesnt help. I've tried everything that I've read on the net and nothing works. Please help. Please !!