Could tell that my dentist only left a small stub of my tooth left, is that normal?

Yes: If you were having a cavity filled or a crown done, then yes, it is normal to feel like there is just a small stub left. Often what feels small to your tongue is still more than adequate to retain a crown, and if your tooth had a cavity, the cavity may have decayed a large portion of the tooth in which case the dentist has no choice but to remove all the decay.

Depends: What you describe as a small stub may be normal to a dentist.. Without seeing your tooth it is difficult to comment upon.. And I am assuming the stub you are describing is after the tooth is prepared for a crown. If there is not enough tooth left the crown will not stay on the tooth after it is cemented and the tooth may need to be built up.