You've Got to Start Giving Yourself Alone Time
I've written before on how important it is to take time for yourself. You need it to recharge, decompress, and prepare yourself for the days and weeks ahead. There's hundreds of studies on introverted and extroverted minds, and how they process stimulation differently.
If you want to see the research, do a quick Google Scholar search. You'll find something worth reading. Rather than going through those reports here, I think it will be much more practical for me to share a little of my own experiences with going all the time and needing to just be alone.
If you have to put me in a box (please don't), you can call me a social introvert. I'm a sociable person, I like to interact with other people, but I reenergize by removing stimulation - by being alone.
The longer I've been married and the more work I've tried to do, the more I'm realizing how important it is for me to take a significant chunk of time to myself, ideally every day. When I say significant, I mean two or three hours. Two or three hours without any pressures from family or work. Just me doing what I want to do, or nothing at all.
Typically I'll use this time productively. It helps me feel better about my day and physically. Like right now I'm using alone time to write. Other times I'll use it to read, or to go for a walk, or even to just lie on the couch doing nothing. This time is important for me. Not necessarily because it's a priority of mine, but because without this time to myself, I become overstimulated and overwhelmed.
Anxiety is essentially a prolonged overstimulation. When you're introverted you become overstimulated much more easily than an extroverted person. It's because introverted minds naturally keep a higher equilibrium of stimulation than extroverts' minds, so any outside stimulation is like throwing gasoline on the fire for an introvert.
Extroverts naturally have a lower level of stimulation, so they're always looking for more of it, particularly through other people and doing things.
My introverted side is pretty strong. My brain is naturally stimulated very easily, so if I don't break and remove myself from it, I start to more or less shut down.
I know there are millions of others who function similarly. There are millions who deal with anxiety daily who simply don't know how to cope with or handle it. The rest of this is no cure for clinically diagnosed anxiety, but prioritizing personal time in these ways will help your body to continually recoup so that you can make the most out of your days and out of yourself.
Decide to take time to yourself daily. Many people will take personal time once a week, once a month, or even less! It's very common for people to wait until they feel like they're about to break before they actually take a break. Ideally, you don't want to ever feel like you're about to break.
Set aside time every day. I take about an hour in the morning before I start really working on anything, and then two hours or so in the evening as often as I can spare. This helps me to both prepare for the day ahead, and to recoup from the probably overstimulating day I've just had.
Make sure to relax by yourself. Trust me. If you've got someone around or music blaring wherever you are, you're still actively stimulating your brain. It might be a nice change of pace, but it's not going to help you recharge. The point of personal time is to remove stimulation so you can function at your top level again.
Use this time for hobbies or fulfilling some passion. You need to take time for yourself. You need to remove outside stimulation. You need to make yourself feel good. What better to make yourself feel good than that which makes you happy?
Using this time for something akin to a hobby helps you be productive with your time. Not that you have to always be doing something productive. But when you do something you feel good about - like small accomplishments and little productive feats - you'll actually feel better and reenergize more quickly.
Overstimulation is a real thing. It's very common, especially for anyone heavy with introversion. You need to take time for yourself every day. Trust me. Without it, I'd be a miserable wreck.
Do yourself a favor. Start specifically setting aside time for you, by yourself, to do something fulfilling for you. If your brain functions anything like mine (I bet it does) this will help you be the best "you" you can be.