I'm too carefree and I don't know how to stop it?

All my friends say i'm carefree and "down for anything" in a positive way but it's actually not a good thing at all. I don't care or stress about things that I really should care about. I don't stress over school, when i fail a test i do feel disappointed for a minute until i move on. I'm still a virgin but i've had lots of hookups with guys i wasn't even dating and I feel no guilt or regret afterwards. No one really knows me that well, including my best friends. I don't trust anyone with my "secrets" or my feelings so I never talk to anyone on that level. I just feel like i'm living for the sake of living, like i'm just trying to make time go by. I'm not passionate about anything and the only people i actually feel love for is my family. Everything else in my life is just temporary including friendships and such...
I'm too carefree and I don't know how to stop it?
Post Opinion