It is EXHAUSTING! Physically, mentally, spiritually, and emotionally EXHAUSTING.
When I had my first son 20 months ago, day and night didn't really matter, aside from the odd doctor appointment. It was so easy compared to having 2 under two. If he slept I slept. Not any more. It's like some cosmic force will NOT allow my two children to sleep at the same time. It actually took me a long time to figure out how to carve out time for a shower. (I was actually given advice on when to shower from my mommy group on facebook)
It is also beautiful. It is beautiful when I see William give his little brother kisses. It is beautiful when William wants to hold his brother. It is beautiful when William comes running over with a paci that he has hid when his little brother starts crying.
So yes, it is exhausting and sometimes I feel like I am crazy for having 2 children so close together, but it is so worth it. I wouldn't have done it any other way.