After dinner yesterday, my big front tooth (upper left one) suddenly started feeling numb and weird. may have hit it on mug last week, can't recall.

Dental issue: Please see your dentist. You need to be examined for tooth damage. Hopefully all will be well but do get checked out. Peace and good health.

Numb tooth: It is possible that a traumatic incident, or many small traumatic incidents over many years, can cause the nerve of a tooth to gradually die. See your General Dentist or a root canal specialist, an Endodontist, for examination, imaging, and vitality testing to determine whether or not treatment is indicated.