Good luck with the surgery!
The only thing I could think when I read your post here was "kid, get yourself a break" - and I don't mean like a big vacation (though that might also be needed if you kept working on this nonstop for 6 years) but like. Get yourself scheduled breaks. People fought in unions for days off for a reason. That's why there is a weekend, to not be cooped up in your work 24/7. Unless you are earning real money to actually live off your comic, make sure you actually get time off (and I mean time off is also important as soon as you can actually earn some money) - make it a 9 to 5 job, or at least don't work more than 10 hours a day.
Creative juices need to recharge and you can't do that if all you do is work on something creative. Give yourself a weekend. If you have the feeling that your content isn't up to par, then maybe that's the simple reason?
Having days off your comic doesn't mean you're not allowed to draw, but maybe if you feel the urge to draw, maybe draw something 100% self-indulgent instead. Get outside and sketch the landscape or your coffee mug while you're sitting on the couch. Draw your favourite character from the latest show you watched. That's okay. You are not your comic and neither is your comic your self. You are allowed to exist outside of it and literally no-one expects you to do otherwise.
Readers, especially faithful readers, are to 99% understanding and I don't think anyone expects you to churn out content all the time. You're not a robot. Your content doesn't get worse by allowing yourself some time to breathe. It might actually enhance it because currently it seems like you're missing out a lot on what life has to offer.
I strongly advise you to look and get yourself a hobby or past-time activity that has next to nothing to do with being creative or making comics. Even if it's just jogging twice a week or playing solitaire in the evening, just something relaxing that still needs your concentration but isn't brain-heavy. That way you can block out your comic for the little time being.
Also, I think the "networking" is mostly just ... bonding with other artists/creatives. If you have a favourite show, find others who like the same thing and talk to them, be nerdy together, create headcanons together and just have silly fun! I got to know most of my artist friends via fandoms, and I think it genuinely helps to already have a wide topic laid out to talk about. And I mean, you're creating friendships there, not just some favour-oweing collectives, so think about what you would want in a friend and then ... be that person to someone else? It's a give and take. If you're not good at making friends - I hate to say this because everyone told me, too, and I hated it - is to just practice and improve your social skills. I'm an intovert. I hate going up to strangers and just start talking and trying to befriend them. I hated this since I was able to talk. But boy the first time I actually talked to someone and they were friendly and, well, befriended me? I have never felt more proud in any moment of my life.
You are 21, you are still a person in the making, and while it is important to have passion and chase your dreams and be hard-working, there is nothing wrong with needing a life outside of that. It's worth it.
Also a small suggestion: I don't know how far ahead you are with your comic but do you have a Patreon where you could give readers early access?
And I mean, you post this comic for not even 3 (!!!!!!!) months, I think 156 subs especially for a newbie without social media are actually quite good.