I'm scared I'm a bad friend

I have friends that I haven't spoken to in a while, about two or three weeks. I feel so guilty, because I haven't tried to keep up with them, and they haven't messaged me either. I feel like it's my fault, because with one of these people, I sent a message, they replied with "that's good," and I never responded back. At the time, I didn't know what else to say, and I didn't want to talk at someone who wasn't interested. I can't ever seem to make close friends with anyone, and I see these people talk to others and freely interact with them. I feel guilty every time there's silence. I worry they just don't like me anymore, or that I did something bad unknowingly and everyone has to keep their distance from me. I don't know what to think. Are they even interested in being friends with me anymore? Is this my fault? Should I have tried reaching out more? Is there something wrong with me that I need to fix?