Congratulations! Your life changes dramatically, but in my experience, I didn't mind a bit! In my case, I had 7 years of marriage before our first baby (who is now almost 5 mos.) and I enjoyed all of the freedom I had, I enjoyed it so much, that I was ready to do something new. So even though I don't go out to the movies on Friday nights and I don't spend an hour doing my hair and makeup- all of those little things I just don't have time for anymore- but I don't care because I love being with my baby and it is worth it.
BEFORE I OFFER ANY ADVICE- I WANT TO MAKE THIS CLEAR: Everyone- even strangers- will offer you a lot of unsolicited advice once your baby arrives- remember- you are the Mom- always reserve your right to nod politely- say "oh what a nice idea"- then do whatever the heck you want!
Babies are expensive- but for us, we don't notice it so much in our monthly expenses. Of course the initial things cost a lot (crib, sheets, toys, car seat- all of that baby gear)- but at the same time, we saved a lot by getting "gently used" things whenever possible. And friends and family bought TONS of clothes- I bet I've spent less than $100 on clothes and we have enough clothes to cover the first year. I am breastfeeding and working so I did invest in a good pump (go for the best- you'll be glad you did). And my husband changed jobs so we work opposite shifts so we don't have to pay for child care. So, other than the initial equipment and doctor bills for during the pregnancy, labor and deliver and well baby checks, weekly expenses haven't really increased all that much for us so far.
Household chores- this was a big adjustment. Again, my husband is home with baby during the day and I'm home at night. So, it took some negotiating but we came to an agreement on who does what. I would recommend picking maybe 2 things that you must have done to feel like you don't live in a mess- for us, if dishes are done it makes us feel like the house is clean- also, we "reset" between shifts. For example: just before I get home, my husband just picks things up quick (dog toys, baby toys, straightens up the nursery, etc.) and then I do the same for him before I leave for work. As for the rest- do it as needed.
Sex life- big change so far. I had an episiotomy and let me tell you, it's been 5 months and its just starting to feel enjoyable again- the first time (6 weeks post partum) was just downright painful. I've also had a much lower sex drive so far. And, because we work opposite shifts, we end up spending time together just catching up. We still have 2 nights a week where we eat together and spend quality time together (our baby is a very good sleeper with an early bedtime)- just be sure you are communicating and finding other ways to be close while your body heals and your hormones adjust.
As far as immediately following the birth: let friends and family help as much as possible. What I found to be the most helpful, was having already prepared meals. My Mom filled our fridge and freezer with casseroles, quick meals, sandwiches- stuff that took just a minute or 2 to heat up and it was so helpful! Those first couple of weeks, you just are so busy adapting to your new schedule that you just don't have the energy to cook- but you need good nutrition to heal your body and, if you breastfeed, to build a good milk supply. So, even if you don't have family to cook for you, I would suggest making meals on your own and freezing them so all you have to do is thaw a nutritious meal.
The most unexpected part immediately following the birth was the sleep deprivation. I had no idea how little sleep I would get. Nobody prepared me for that and it was the hardest part for me. Tips that I can't emphasize enough: 1) sleep when baby sleeps 2) learn to breastfeed in sidelying position 3) get your spouse to help- for example: when it's time to feed baby (you have to wake the baby at night those first few weeks to feed-especially if breastfeeding) have your spouse wake the baby (sometime this is more difficult than you would expect- for us it was a process of changing the diaper, rubbing baby's arms, legs etc to wake him before I could feed him) bring the baby to you so all you have to do is feed the baby, then have your spouse take the baby back to bed or, soothe the baby back to sleep. For me, at about 4-5 weeks is when I stopped waking the baby to feed at night and only fed him at night if he woke on his own for feeding. So for the first 4 weeks, the most I slept at a time was maybe 2 hours. By 5 weeks I was getting blocks of 3 hours of sleep. By 8 weeks closer to 3-4 hour blocks. By 3 months one 5 hour block a night and by 4 months he was sleeping 12 hour nights (once in a while he'd wake briefly in the night)- but then it was easy to get sleep- I did get up once in the night to pump though.
If I had one book to recommend to you, it would be "Healthy Sleep Habits, Happy Child." I don't know where I'd be without that book. I not only learned about my baby's sleep patterns, but my own. And, like I said, I am thrilled that at 4 months, my baby was sleeping from 7pm to 7am.
The biggest tip: be flexible. Babies change so rapidly- physically, emotionally, sleep habits, eating habits- just when you think you have it all figured out, baby will change- but you get better at noticing the changes in patterns and it gets easier to adjust.
If you choose to breastfeed- don't let anyone tell you it doesn't hurt- it hurts like a son of a gun those first 2 weeks- but I swear- it gets better and by 4 weeks- you'll wonder how it was ever difficult to begin with. 2 things: Lanolin on your nipples after every feeding and after showers and Soothies- they'll get you by. Just be patient with yourself and with the baby- you are both learning a new skill.
I hope you love being a Mom as much as I do. It will be challenging, but you will figure it out- just take everything one step and one day at a time.