Navigating life and social situations as an adult

I've graduated college. I've turned 21. I should be able to handle social situations, but no. I keep making foolish decisions. Sometimes, I know the right thing. It nags at the back of my head but then I overthink and doubt myself, and end up making the wrong decisions. Or I overlook and underestimate the importance of something.

This is something I should have worked on by now or figured out, but I keep trying and trying, making mistakes upon mistakes, identifying where I went wrong and trying to reflect, yet when I find myself in a similar situation, it's like everything I've learnt flies out the window. I make another mistake. Identify what I did wrong once again, reflect, tell myself I'll do better in the future, rinse, repeat.

Sometimes the wise choice is in my head, and somehow I end up with the foolish choice and then when it comes tumbling down, I ask myself why didn't I follow the wise voice at the back of my head. I don't know what to do again.

I don't leave the house since I don't have a job yet, I mostly stay at home alone. Even when the rest of the family come home, I hardly feel like talking to them. I have friends, but again, not really. I hardly interact with anyone nowadays.

I need to get better and I need to get better now.