Would you go back if you could?

[NEC]

I don't hang out with them as much (I found a post on my mom's FB where she said "back when brian used to like us," which really tore me apart

Let them know you love them. Make sure they know you're greatful because of everything they have done for you. Communication is important.

Also, the fear of losing your parents it's normal.

When something gets stucked in my head (like this happens to be your case) I just lay on bed and think, sometimes I talk with myself out loud. Hearing things helps me get perspective, even if I hear them from myself. If you have a really close friend, you could try talking to him/her too. Sharing my feelings has always helped me.