I had my kids 18mths apart. I know exactly how yu feel. It's so much hard work isn't it.

To be honest it got better for me once the eldest one started Kinder. They're 10 & 12 now and still fight like cat and dog but it's NOTHING compared to having 2 toddlers.

Are you able to have them in child care once a week for your own sanity? I found that having 1 day a week 'off' helped me deal with them better.