Welcome to Tapas! That's super exciting and yes, stressful too!). But either way, I hope you enjoy your time here!
I can sympathize with all of that anxiety. It's really hard putting your stuff out there (especially after putting so much love and care into it and then releasing it for the masses). Letting your heart bleed on the page and only hearing crickets for a while can hurt BUT I can pass along a few tips I've learned along the way (some the hard way, and some from many other lovely creators who have helped me with my anxiety (and there's a lot of good advice here already).
First, no one knows you better than yourself, so know when you need to walk away from the Internet for a bit after posting. Sometimes I find it helpful to post an update right before bedtime so I can just tune it out and I'm not tempted to return and look at my numbers. Take care of yourself first and know when to walk away (and who to confide in because it is really tough to put yourself out there). Having someone around who you can just be a puddle with is helpful (and if you don't have that person, I know you can find them here (at least in spirit)).
Next, focus on making your comic the best it can be. This is your passion so give it all the love and attention that you need to. Numbers don't matter, the work does, and as long as you do some self-promotion, you will find your people (either through the right promotional thread, or perhaps, more typically- through a common interest thread). I've made my best connections OUTSIDE of promotional threads (and avoid "Sub-for-Sub" promo threads like the plague. Not only do they not help you (I know, the extra numbers are SO tempting (and I've given into that temptation)), I can assure you, it's a hollow venture. You want readers, not dead subs. Dead subs hurt you in the algorithm used for the "NEW FROM COMMUNITY" section too. Yes, you get a bit of a dopamine rush from getting a new sub (from the sub-4-sub), but if they don't actually read your work, it won't get you closer to your goal (and eventually, they'll probably end up dropping your subscription later on down the road (and OUCH, the dropped sub hurts WAY more). I've seen a few people drop off my book from the sub-4-sub threads, and it hurt at first- but now that I have a few steady, active readers, it hurts less (because the dead sub subscription was hollow to begin with). Look for nice threads to interact with other creators (I love the "Sketch of the Day" thread but there are other good writer threads too, depending on your area of expertise).
Finally, since this is your first posted story, it may help to think of this as a "soft opening." It's rare to be a newcomer and have a meteoric rise, so hope for the best but expect far less. This is just the beginning. Be gentle with yourself and try to enjoy Every. Single. Milestone (from hearts, to subs, to comments). They'll come. Your jam will be someone else's jam, they just need to find you first.
No matter what, do your best work and have fun with it (and set goals for what you want to GET out of posting). Is it to be better at your craft? To form a following? To find community? Whatever it is, you do you (and work toward being the best you with the best work possible.
And it's cool that you let your anxieties be known. There are LOADS of people that want to help, so good on you for putting yourself out there.