What should I do about breaking my vow to God to abstain from smoking after returning from Hajj, and is this considered a breach of a covenant with God that leads to His wrath?

We ask Allah to accept your Hajj and make it a Mabrur (accepted and righteous) one. We advise you to strive hard to quit smoking, strengthen your resolve, and seek help from Allah, especially since you have made a covenant with Allah to abandon it.