My dog died 4 months ago

My dog died four months ago, but for some reason, it still feels like he could still be around.

At first, when he died, I cried for days because the thought of him not being around hurt so much. Then I finally accepted this and did my best to move on. But now that I have, it strangely feels like he is still here.

The other day, I walked past one of the rooms, and I swear I saw him lying on the rug. But it's like I saw him in my mind's eye rather than with my actual eyes.

Has this happened to anyone else before?