I'm not sure how at 21 how your parents are "not letting you" live in your own apartment. You are past the age required to enter into contracts on your own volition. If you are employed and have a steady income, it should not be difficult to sign a lease to rent an apartment.
That said, it sounds like your parents are opposed to the idea, and it is quite possible that it could cause a rift in your relationship with your parents should you chose to go against their wishes. Those consequences is something you have to weigh yourself. Some parents would be upset for a little while and then forgiving once they see responsibility demonstrated, others might disown their kids and refuse to ever talk to them again or write them out of the will or the like. I don't know your parents, you do. You have choices, but you are the one who will have to deal with the consequences.
In fact, you may in some ways be currently dealing with the consequences of your previous bad decisions. You may have lost some of the trust of your parents. They may be questioning your judgment, whether you are likely to make additional bad choices, and so on. Trust is earned, not given. You may have to work to regain their trust, if that is important to you.
While it is often true that is is hard for parents to come to accept that their children have grown to become adults, you may also wish to reflect upon whether your behavior contributes significantly to their perspective of as a child vs an adult. One thing that jumps out in your post is the title of your post. It sounds a lot like the typical teenage refrain "My parents are ruining my life", often accompanied by teenage temper tantrums with slamming doors, yelling at parents or calling them names, saying things you don't mean like "I hate you mom" and so on.
As you get older you start to appreciate that even if you don't agree in every way with your parents, they have many years of wisdom and experience and, no matter how misguided their efforts may (or may not) be, it sounds like they are really trying to look out for your well-being, not trying to harm you or destroy your life.
It sounds like they are trying, as best they know how, to express their loving concern and try to make sure you're headed in the right direction. I'm sure they've been around long enough to have plenty of life experience and know how the saying goes "bad company corrupts good character" and they're probably trying to look out for what they see as your best interest. They want to make sure you're keeping good company and not surrounding yourself with situations that are going to bring you misery or financial ruin or the like. Perhaps they are being a little over-protective in doing so, but keep in mind, it's not out of an intention to interfere with or ruin your life, it is out of their desire to help guide you to make better choices so you won't suffer the consequences poor choices might lead to. Perhaps you desire a lifestyle they don't approve of--but only through mature adult conversation can you really understand their concerns and why they do or don't want for you the things you desire.
You may need to step back and let some of the strong emotions about the situation cool off before discussing it further with your parents or making any decisions you might later regret. Think through your thoughts and your choices, and get things clear in your head. Erase the attitude that they're out to get you--if they were, they probably wouldn't have taken you, as an adult, back in their home and been willing to support you and feed you while you transitioned back to your home country, they would have instead said, "good luck, let us know where you'll be living, hope you find a job soon and don't end up on the streets!"
You can choose to try to understand their perspective and concerns and how they compare to yours. You can then try to convince them their concerns are un-warranted or that you're responsible and they don't need to micromanage your friendships. Or you can ignore their advice and concern and forge your own way, for better or worse.