How can a person who does not believe in life after death commemorate the dead?

Today is my birthday. Today is also my mom’s birthday. She died a little over 3 months ago.

I am feeling a bit empty today, but I have no idea what to do about it. I have no spiritual beliefs or religion, so I feel a bit silly feeling like I need to somehow connect with my dead mom.

What can I do? Any suggestions? If you are a non-believer like me, what do you do in cases like this?