I found out I was pregnant with my second when my eldest was 9 months.
I felt all the things you're feeling- it's too soon, so I want this, this will be so unfair on DD1, I'm NEVER GOING TO SLEEP AGAIN.
Fast forward 2 years 9 months and my 2&3.5 year old girls are thick as thieves. They play and fight together and are totally utterly exhausting. And I wouldn't change that.
It's incredibly hard. We were so skint for a while paying for 2x childcare without the 3 year 30 hour funding that for a while we had to literally scour the house for pennies.
It's so so tiring. But the light is at the end of the tunnel in terms of going out on dates, we've started sleeping through (as a family lol) and this summer I will hopefully change my LAST NAPPY!
At a time when all my friends are thinking or are already parenting/pregnant with their second child, me and my husband are getting our lives back.
All in all I equate it to ripping off a plaster rather than pulling it off slowly.
Whatever you decide best of luck