I was slapped hard in the ear and it has been about a week and i feel like there is fluid stuck in my ear?

Perforation: When slapped with a cupped hand, tympanic membrane perforation is common. See an ENT doctor.

Ear discomfort: It is quite possible that the trauma of your slap resulted in some fluid behind the ear drum since that is a general response to injury. It is also possible that you may have suffered damage to your ear drum from the slap and that it just feels like a fluid sensation. Have your primary medical doctor take a look and get to the bottom of this. A week is too long for this.