Help! change status B -> H-4->TN

I am a Canadian citizen in US with my wife(H1-B). I've been in US for more than 6 months and filed application to change my status to H-4. Is it true that Canadian citizen can not change immigration status within US because we don't have I-94 with B visa? Does it make my stay illegal at this moment? My application hasn't been processed until now and I just got a job offer(Engineering) and ready to go to the border for the TN. My question is am I going be hassled at the border because of the overstay?

Had your 6 months allowed visit already expired by the time you sent the application for the H visa? If it had, yes, you may be hassled because of the overstay.

If however you had applied to extend your stay before your 6 months are up, then you haven't technically overstayed, I think they consider your status as legal, but pending decision.

If you leave the country however, and if they deny your TN visa, you may be subject to a ban, depending on how long you have overstayed.

Thank you for your input.

I filed my application before 6 months were up (expired on Auguest 15) and got the Receipt Notice in July. Should I wait until I got the H-4 or just bring the Receipt Notice along with TN application to the border?