Stop other devices from getting my iMessages

my mom and I share the same Apple ID. We've never had a problem with our texts getting sent to the wrong device. I always make sure that only my phone number is ticked in the send and receive setting. This morning however I turned off my iMessage for about half an hour, when I turned it back on I noticed my texts were being read by someone else because the blue bullet wasn't marked and I knew i hadn't read some of those texts. next thing I know whoever was getting my texts responded to one of my text strings. It appeared to them and me as if I had replied, but it wasn't me or my device. I live in a different town from my mom so I'm not sure if it was her but im almost certain it was. I went to my settings and noticed only my phone number was still ticked so I'm so confused now. now as a last resort I went to setting > messages>send and receive and logged out of my Apple ID from there, once I did that the email associated with my Apple ID (which wasn't ticked) and my moms phone number disappeared, leaving only my number. I'm still able to use my iMessage, so I'm just wondering if this solves my problem of my mom getting and responding to my texts?