Taking life too seriously

Any tips or advice on how to not take life too seriously? I’m 26 and I always think back to when I was like 18-19 and for the first time in my life I didn’t take life too seriously, if someone was rude I’d just wish them a better day instead of letting it ruin my day, didn’t care about someone who didn’t like me, didn’t take life too seriously I was just super chill and lately I been thinking back to that time and wondering how did I lose that mentality. At the moment I feel like I take life too seriously and idk if it has to do with getting older and having more adult everyday stress but I would love to get back to how I was and don’t know how. I feel like I used to be more positive when I was younger and now I feel like I’m pretty negative with my thoughts. I’m sure a lot of people struggle with taking life too seriously and I’m hoping to get some advice on how to chill out. I feel like I get angry easily at everything, I hate people, I have zero patience, little stuff bothers me, etc. (I’ve always hated people and have been an introvert btw) My husband and I are also in the process of owning a business and all that legal stuff so that adds stress and then I am also dealing with my mom having cancer and the constant anxiety of being afraid to lose her doesn’t help. I know I am not the only one that has issues in life but it would be nice to get some feedback on people who have worked on not taking life too seriously and could help me out with tips on how to get there again because it’s a much better way of life. Thanks in advance.