It's incredibly challenging, perhaps look up the recent thread a woman made about how boring she finds having he child? I can't remember exactly what she said but it does show an honest picture of how draining some people can find it.
Personally, I love it so much and we are about to start trying for our second; though we are having an larger age gap than planned, at least 3 years rather than the 2 we thought we wanted, because it is bloody hard.
My husband would probably be okay with only having one but I really want 2 and he knows that in the long run it will be worth it, just that having 2 young kids is going to be really difficult.
I definitely miss having time for my hobbies but I do really enjoy spending time with my daughter and I know that as she gets older these moments will be gone and I'll have more time to myself again.
I can read books and go hiking when I'm 50, but my daughter will never be 2 years old again so I really try to enjoy every moment I can.
Travelling has not been a problem for us, but we found extended bed sharing and breast feeding really made the long flights and hotel rooms easier. Some friends didn't even travel abroad with their kids until they were over 2 but we've been to 7 different countries with our toddler, mostly long distance. As others have said, lower your expectations, slow the pace and make sure you include things that your kid will enjoy too like finding a park or kids museum.
I am also very prone to depression and anxiety and was really worried about that but I found letting go of worrying about milestones and doing the same as everyone else was with their baby helped so much. I really thought that I would be the person who had a set schedule as that's very 'me' but I was much happier going with the flow and being flexible and it took so much pressure off.
Cultivating your mum friend group helps here too, if you want to be relaxed and flexible your mum friends need to be too otherwise you'll be around people who are constantly comparing or can only meet up for 45 minutes because of the nap schedule. Which might be what works for you, so choose friends who are mumming in a similar way to you!
Your relationship with your husband will suffer, you'll both be overwhelmed, and overtired and you will lash out at each other. Try to remember that those bad times will be temporary if you can find the good moments and enjoy them and give each other as much grace as possible. It sucks but we found the best solution was giving each other space where possible, so letting each other have total free time to relax.
To have any kind of semblance of me time though, we have had to lower our standards around organising, cleaning, tidying, gardening, cooking, self care etc. Which has worked for us but might not for others. We prioritise spending time with our daughter, together and relaxing when we feel overwhelmed. We don't worry that the house isn't as clean as we'd like, that we've got several admin tasks that aren't quite up to date and that our garden is like a jungle. I have no skincare routine anymore because I'd rather get into bed earlier or read a book than worry about 6 steps of skincare. We take shortcuts with our cooking whilst still trying to stay healthy, we just do much simpler meals and lots of repeats. Your time just reduces so dramatically that we had to sit down and realise that we literally couldn't do everything that we wanted to, so something has to give or you'll burn out totally.
A big thing that I also had to accept is that your child will have a personality of their own when born and that means that they might not fit into the plans you had or behave like other kids. Try to find the positives and learn to adapt.
Yes children should fit into your life but they are also their own person who deserves a space for themselves, not just to be forced into the space we have decided to allow for them.