Doubting myself and anxiety

So I had this website idea, I got so excited, I lied awake all night planning, planned for days on how I'm going to do it, got myself a project planner, got pages written down, during baby naptimes I've been working on the website, have my own domain, buisness email which actually looks professional (my name@brandname.com basically), I've made a fb page, Instagram page, ready to market, my website is designed and ready for launch, the last step now is contacting various people if they would like to join me, the whole idea is supporting them, at no cost to them, completely risk free, no contracts, they'll get 100% of what they ask for, I'm not going to be their boss, its sort of like I'll be a friendly assistant to them offering support as I bare the stress of domain costs, shipping costs, customer service, advertising oh and I have an amazon sellers account which they could take advantage of but I'm the one in control and I know how I'm going to get those costs reimbursed through the services, don't expect profit for a couple months, I also have spreadsheets made and ready to start accounts for bookkeeping purposes, I also have a second number for whatsapp buisness to give to the people wanting to work with me, I'm in the UK and I don't need to register anything just yet so there's no stress yet of VAT or buisness registering but I know the income threshold of when I should register, I have qualifications in buisness and accounting so yeah, I'm basically ready, all has been sorted.

But now that I need to reach out to other people, I'm getting anxious, thoughts run through my mind like who do I think I am, doubting ill even be able to pull this off, I'm scared to fail, my partner is 100% backing me, his probably sick of me complaining about being a SAHM for the past 5 years and having 2 kids, not doing anything fulfilling (although I do love being a mom, I just feel useless) apart from studying.

I was actually ready to start finding people on Saturday but I thought Monday would be best as its a "buisness day" but Monday came and the doubts came, I went out hiking with LO while my oldest was in school, Tuesday came and again I did the same, now it's rest day as my legs are aching, but instead I'm sat here writing this as LO sleeps. Ugh I hate this, before thinking of writing this I even thought to give up, give up before I even started because of doubts?! How stupid is that.

Anyone got any advice? I'm a socially anxious, overthinking person, I almost want to just throw myself in without thinking but I open my laptop and I get scared

Just my partner and I have gone on a hike alone a couple times to talk through and he has been challenging me by asking many various questions and he did make me feel like I can pull it off, he believes I can, I'd love to have him by my side but he works 60 hours a week 😩