It took me a GOOD 2 years before I even started to feel a little content with staying home. It was a huge adjustment going from the workforce to being stuck at home. I felt very isolated despite being constantly busy. I think that had a lot to do with my previous line of work.
My first two are 15 months apart. That made things a little more up beat but I quickly fell pregnant with #3 because I was 'bored, home anyway, planning on more eventually so may as well'.

It was the 3 under 3 that made me feel somewhat content. Now I am expecting #4 in 5 years and I have finally got to a place where I am comfortable being at home. I guess I am finally 'broken in'.

I do have plans to go back to work once the children are a little older. It was an extremely hard adjustment for me but I finally got there in the end. Some people might not ever get there and that's completely fine. We all have to find our own groove.
Hopefully you'll get there and find yours too!