koneko has offered some really good advice and there's not much I can add that'll do any good.

I can say that I relate. My family, bf's family, and bf all want us to have kids...and I'm not necessarily opposed to the idea but it scares the ever-loving crap out of me, from carrying to delivery to rearing. I have a lot of problems and zero self-control and fear what kind of mother I would be. :c And to think people just...casually, even accidentally, do it on the regular! Like bRo there's a whole little PERSON in there.

There is the possibility of preserving some eggs and trying in-vitro or surrogate conception down the road, though! If nothing else it's an idea to throw around.

Can you pinpoint any people or things that might be the source of your anxiety? I.e. do you feel any pressure from your family about having kids? You seem pretty resolute in your decision, so I'm inclined to believe your anxiety is more so coming from satisfying the expectations of your family, or for instance the people you've mentioned who expressed their regrets.

I feel like older folks (even people who are only marginally older) have a tendency to project themselves onto younger people in terms of what we'll regret, what we should / shouldn't do, yadda yadda... And of course there's something to be said with the wisdom that comes with age, but... It's kind of like the tattoos debacle. Bring it up in a crowd and there will always be people who say "Don't do it! You'll regret it!" but those people, 90% of the time, don't even have tattoos, or got really cheap / cringe tattoos that wouldn't look good on anyone. (Contrived but you get my point.)

That being said, I also have to wonder if you're bound up in knots about it because part of you does want to have a child, but have spent years with the expectation that it would never happen, and it's a piece that doesn't necessarily fit into your Life Puzzle right now. (I'm sorry if that crosses a line or makes you feel worse D: but I do think it's a question to ask yourself). Thankfully, though, life is fluid.

Figuring out the root of your anxiety can help you find the next step to figuring out the whole issue itself. So I definitely second koneko's suggestions of looking into all the nitty gritty, immersing yourself in it, imagining yourself in all the best and worst spots of it.

Either way, I hope you're able to get some answers and put your anxiety at ease. <3 Good luck.

I have a different perspective to give, I have one biological and one adopted, they are only a few months apart. My maternal instincts aren't as strong as other parents. I'm all about giving them life experiences and talks that help them understand their feelings. I parent differently than anyone I've met, probably more of a 'country style.
I'm tired often and run out of energy rather quickly. I knew that going into being a parent and so I plan accordingly. I guess I'm raising my kids to be independent fairly early. I'd go into detail- but that'd be paragraphs long. lol.
I wanted to say that when my biological kid is distressed my whole body reacts. It's such a wild primitive feeling. When my adopted kid gets distressed, I am calm and I know I need to stay calm to help her through whatever it is that is wrong. [a cut, emotional turmoil, etc]. I got her at 2 years old and the trauma she already dealt with took years of therapy and doctor's appointments.
Finding babies that are up for adoption is pretty difficult and can be expensive. So if you choose to adopt, I do recommend a toddler, butttt- expect trauma, even if it's not obvious immediately.
-
on a side note too, I have 2 sisters who didn't want children and their kids are difficult. o;o" I used to babysit them often. I helped raise them when my sisters needed breaks. Oof. They're all teenage kids now and they know their parents love them, but one of my sisters has an obsessive love and my niece has no freedoms and my other sister gave too much freedoms, and now being home with her kids is torture for the whole lot.

I don't want to sway your mind, I just wanted to give you some of my personal experiences to read.

Well first my Child was an accident but i always wanted a Child so in the end iam Not mad about this situation. The only thing i can tell you is that I as a parent totally can understand your reasons for not wanting a Child. Its Not a thing for everyone to raise one. Its tiring and so irritating you have new anxieties, simple you bind your life fully on another human being.
Not to mention iam made for parenting and i would be empty without my little bug! But its totally fine if you and Your husband dont want to! Enjoy your life as it is :)))

@totalanimefan: Look want kids when I am older but I know it is hard to raise one I was 6 when I had to take care of my baby brother. I raised him and I know that my bio mom regrets putting that weight on my shoulders but I learned how hard it is to be a parent but at the end of the day I loved doing it. I loved taking care of that tiny baby and raising him. I am adopted because my mom couldn't have kids. She got me at 13 and I am 18 those 5 years that I have been with my mom have been the best. Your kid if you have one will Love you and hold you dear come home with homemade mother's day gift and cards and will draw you pictures to show that they love you. I won't ever regret having a kid because I know I will raise my kid better than I was raised and I know that they will be a good person. I want to say that you will be a great mom I can tell I have had some shitty ones but you will be able to understand what your kid needs and you will able to show them the beauty of life. There is a ted talk that I want you to listen to I think you will like it. here it the link.