Filling only fills my molar by half(?)

[Alison]

So I just got a filling done for the first time (I'm 19) because I had this big cavity at my backmost left upper molar, I could see that the hole was blackish and stuff by looking in the mirror. I just came back from my filling an hour ago and I can feel that the filling doesn't 'refill' my tooth, it only fills it in halfway (half that's towards the front/entrance of the mouth) and I think the rest got kind of drilled away or something. I can still see the black edge where the cavity was from before. Is this normal?