Just because someone asks you to do something does not mean you are obligated to do it. If they want to do something with you but you don't want to do something with them, they shouldn't get their way over you; what you want matters, too. Some friends can be pushy and will try to convince you to hang out even after you have said that you can't. Keep firm in your decision by re-iterating your reasons for why you cannot attend.  To keep it friendly you can (if applicable) try joking around about the last time you asked your friend to do something and he said no. This will remind him that he has turned down your plans before, too, so he especially shouldn't be trying to guilt you into doing something. As long as you offer a sincere apology and do your part to maintain the friendship, you are not responsible for how your friend reacts to your turning down his plans.  Ultimately, it is up to him how he decides to respond to your refusal to hang out. Keep that in mind if you are feeling down about your decision to turn him down.  Try not to be afraid of how your friend will react. Again, as long as you are doing your part to be a good friend, you don't have to make plans with your friend every time he wants. If he reacts really negatively to your turning him down, perhaps he isn't the best friend to have around. Keeping that in mind should help alleviate your fear of his reaction. You can't do everything that everyone wants all the time, even for your friends. You have other commitments and responsibilities. Sometimes in life there are things that need to be done that are more important than socializing, such as working hard to become more financially stable, so you shouldn't feel too bad if you can't make plans.
تذكر أنه من حقك الرفض. لا تُلقِ اللوم على نفسك. تذكر أنك غير مسئول عن رد فعل صديقك. تذكر أن وقتك محدود.