To be successful you probably need to create more concepts, do spec-work, etc., so you have an amazing portfolio. Then you need to market yourself vs. banking on people coming to you.
For instance, if your specialty is rebranding, how are you demonstrating those skills to prospective clients? If your portfolio site doesn't have a section of rebranding concepts you've created through existing work or concepts, then get to work. Choose brands you like and would one day love to work with, and think of what you do for their logo, website, etc., so you can attract clients who are looking for rebranding.
Then think of ways to get your name out there. If you're not using social media (YouTube, Instagram, etc), to put meaningful content out there then your behind the hundreds and thousands of people in your market who are willing to do that. Using the rebranding example, show before and afters, explain when it's time to rebrand, explain how rebranding is an "evolution" and not something that's done overnight, etc. Create a blog, so you have a place on your website where you can explain all of that in written form. This way you're answering commonly asked questions about rebranding, and people can discover you when they're searching the internet.
Without knowing what you have done already to try to be successful, it's tough to say "do this or that." But having mentored lots of entrepreneurs, worked on startups and turn arounds, the thing most of them have in common is thinking they're doing a lot and just not getting the reward of clients and income. When in reality, they aren't doing much, so their income reflects that.
Take a moment to evaluate yourself, and do it objectively. Can you honestly say you want success as a graphic designer more than anything else and you're doing everything you can to achieve it? Next reflect on how much time you spend with friends, going to social events, watching TV, playing video games, etc? Are your actions matching what your perceived effort is? Remember, you're not giving up other areas of your life forever, but if you're not eating sh*t for 3 years to grow your business, then you're not trying. After 3 years, you have to ask yourself if you have a business or a hobby and whether the juice is worth the squeeze.
Also, my marketing agency designs and builds websites. Sure there are people on Fiverr, and overseas who can do it for a lot less, but those aren't my clients. So remind yourself that there are people who are willing to pay a premium if your quality of work, and service match that level. We live in a world where some people drive AMG's and others drive Elantra's. So don't let people take your dream away either.
I guess that's my longwinded advice.
A friend of mine works for SAP Concur (I think that's the name of the company), but hated his first position there because it was mostly cold calling. However, he loved the paycheck which was about $8-10k per month before taxes. It took him about 6 months to get to that. But I'll also say, he was exceptional at sales, whether it was in person, phone, or virtual. It took him a little more than a year and a half to be promoted from that position.
With that said, if you only have $300 to your name, get any job you can right now and start putting money in your bank account so you won't be worrying about paying bills, feeding yourself, etc. It's impossible to think about other needs when the basic ones aren't taken care of. Then while you're working the stop-gap job, you can look for ones you actually want. Even outside of holiday, the Target and Costco in my area has been looking for employees. I think Target was starting at $19/hr and Costco was $21/hr. I know it's not glamorous and you'll have to suck up your pride a little, but again it's a stop gap to take care of basic needs.
Anyway, I have friends in software, and medical device sales. They have been doing it forever, and while they bitch about their jobs they don't bitch about their checks. All of them make 6-figures. Then you can use your free time to grow your side-hustle, and hopefully one day it becomes your full-time and grows huge and you have your own employees. At your age, you should be taking risks - but shouldn't be putting all your eggs in one basket either.
Just remember, you don't always have to love what you do, as long as it allows you to actually do the things you love. And in the process, you might discover the self-employed life isn't for you, and that's okay.
Good luck and post updates on your journey!