Magic Forums

A few nights ago, I attempted to summon a familiar, today I began searching for my possible familiar in a park (someone told me to look for the familiar). I decided to give up, until I was just standing in front of a bush, eating, and a rat (or mouse, but it looked more like a rat) scurried out in front of me, looked up at me, I think I must have flinched because it scurried away after a few heartbeats of starring at me. The only features I remember was it had golden-brown fur and blue eyes (from research I just did, I don't actually think that's possible).
I didn't see it come out from the bush, and when I inspected its hiding place, it was gone. as if it just vanished into thin air.
The blue eyes is what hit me, last night, I dreamed of being watched by a pair of glowing blue eyes, and the rats eyes must've been noticeable, considering I was only looking at it for a few moments. (I would also like to mention the rat looked fairly healthy, I feel like that was an important fact for some reason).
In the dream, the blue eyes turned into a patch of stars, then the dream ended.
I don't know if this mouse was my familiar, because a mouse seems like an unlikely partner for me, I was expecting more of a cat or wolf kind of thing. But hey, it was a cute rat!.
And that brings me to my second question, can familiars change forms? From my research, it is possible, but what do you think?
Thanks!