It's scary, eh? I totally know.
I hated my job/work, wasn't making lots of money, was bringing home pennies and dimes compared to DH's salary, and knew I wanted more than anything to stay home with my children....and it was STILL a scary decision!
I think it's really important to look at your finances with a very honest and critical eye. You might have to prioritize and make some choices to do without certain things that aren't necessities. But, I think the good news is that...babies don't have to be expensive! Especially not in the first 2 years! You don't need all the expensive gear! Most of what you need you can ask for as gifts, or get second hand. Somewhere to sleep, someway to carry them, a car seat, some clothes...that's about it for the first few months.
Budget isn't really an issue for us but I still try to buy the majority of DD's clothes (and things for the new baby) at the thrift shop - seriously, for the first year's sizes you can get a whole wardrobe, practically brand new, for 1/10th of the original cost. What I don't buy at the thrift, I try to buy from the clearance racks - and I try to buy in advance sizes when I see a great deal. Ditto for books and toys!
Honestly, our biggest baby expense was formula because we couldn't breastfeed. If you can and do breastfeed, you're way ahead!
Baby food? We did baby led weaning and she ate what we ate - real food! no expensive bottles or jars or boxes.
Be sure to factor in the ways you'll actually SAVE money - by being home you can meal plan, cook from scratch, stock up on sales, take better care of your belongings and clothing so they last longer. You won't need clothing for work, or transit/gas for work, or lunches etc. What would daycare cost you? What would be left from your salary after paying for daycare (and potentially formula if you wean early?) and work related expenses? THAT is the amount you are actually looking at doing without.
As for the free time and fulfillment questions.....well....I won't lie. The first year with a baby is hard. The second year with a baby is hard. Everything changes as soon as you have it figured out. There were times in the first 6 months I would have sold my kid for a cup of tea and an hour to myself (not really ;) It can be very stressful and hard learning to parent with your partner. My DH works ridiculously long hours so I was, and am, alone with the baby and on duty for most of the day. Sometimes he is only home for an hour before she is in bed. Sometimes, he's not even here for that. It's hard. You have to just squeeze in every moment you can for YOU. Read a book while they eat their lunch. Get a babysitter once in awhile and go get your hair cut. Don't feel guilty about relaxing when they nap. Accept help when it's offered.
FIND LIKEMINDED FRIENDS. Seriously. I am not a joiner, and I`m a bit socially awkward, but finding a small group of mama friends who also stay home has been like a lifeline. Playground dates, coffee dates, sit in the backyard and blow bubbles dates....someone to call who GETS IT, someone whose advice you trust, someone to call if something comes up and I need someone to take care of DD on short notice. Priceless.
Once DD turned 1 I would say I have had a fair amount of free time - time during the day I could steal to work on my own stuff. I'm savoring it now because I know once the new baby comes it will disappear again for awhile.
It all gets easier. It all goes so fast. I know it's cliche...but holy crap, my tiny baby is 2+ and about to be a big sister...I am absolutely gobsmacked when I think about how I was so impatient and eager for her to be born...and now she's practically grown up! (Pregnancy hormones may be making me a little emotional and sentimental at the moment...)
And...It is honestly, the most fulfilling, important, amazing, beautiful thing I have ever done. she changed my life. She changed my priorities. She made me so thankful for every second I get to do this job. No amount of sleep deprivation, puke, chatter (mama, mama, mama, maaaaammmmaaaaa...) has ever made me regret being home with her. I am so thankful I have gotten to witness every first, and get to know her better than anyone. I try to enjoy and soak it all up.
When I imagine having her in daycare - running back and forth dropping her off and picking her up, dealing with sick days, rushing home to get supper ready, seeing her only at the end of the day when she's hungry and tired....gosh, that makes me sad.
Now, like I said - I hated my job. It didn't matter. I was pushing papers. And I ENJOY the things that come with staying home - I like keeping a home, taking care of and feeding everyone well, making things beautiful and welcoming, growing a garden, having the time to sew and knit for DD, creating a nice place for her to play. So, take that into account - I`m biased. But then, I also have to do these things because as I mentioned, DH is rarely home to do them. You should really be clear with your partner about what the division of household work will be for you. Staying home doesn`t have to mean you are also the laundry fairy, cook and maid! But it might be assumed unless you talk about it.
So yeah....becoming a mother and staying home have brought me serious joy. But it`s hard. But it's worth it. And it goes by so fast - it's clear to me now that there will be plenty of time in my life to do things for me (work, school, etc) if I want to...but this time is precious and fleeting.
Ahem, so there's my novel.