Don't grind teeth @ night. no pain or issues but bottom front tooth pushing out a bit. did the few times i clenched teeth while under stress cause it?

No: A short lived clenching habit will not cause problems. However, most patients are unaware of these habits and often have them longer or to a greater degree than they are aware of. Other dental issues (such as periodontal disease), tongue thrust, etc. can also play a contributory role.

Migration: Teeth want to migrate toward the front and to erupt to compensate for the wear that we don't have, but that our Stone Age ancestors did. There are many reasons for destabilization, and the result is not self correcting. See a fully qualified Orthodontic Specialist to discuss your issue.