Marriage is always presumed to be valid unless a valid tribunal (or the bishop ordinary) finds otherwise. Can 1060, 1107.
Impaired judgement, provided coercion was lacking, doesn’t axiomatically render it void. He would have had to have lost the use of reason. Mentally ill folk are allowed to enter valid marriage, after all, provided they have use of reason, understand the nature of the commitment, and are not otherwise impeded (by ordination, impotence, prior marriage vows, or other impeding vows.)
If you have reason to believe he was beyond use of reason, talk to your pastor about it.
Also note: Giving Consent prior to the wedding itself (which is a normative part of the preparation) is normative. If he was sober and manifested consent prior, his being intoxicated during is only a minor issue, provided he was still able to use reason, and gave that same consent then.
Further note: almost every marriage has periods of regret. It’s normal. (The Devil hates marriage.) Despair not. (The devil loves despair.)
And another note: the status of the priest is almost immaterial - if he was granted the faculty to witness weddings on behalf of the church, the marriage itself is valid, since that faculty can be granted even to laymen. (Can. 1112, 1116). If he was invalidly ordained, the blessing would be invalid, but not the marriage, as you as a couple consenting makes the marriage. (Can 1057)
Can. 1057 [INDENT]§1. The consent of the parties, legitimately manifested between persons quali-fied by law, makes marriage; no human power is able to supply this consent.
§2. Matrimonial consent is an act of the will by which a man and a woman mutually give and accept each other through an irrevocable covenant in order to establish marriage.
Can. 1060 Marriage possesses the favor of law; therefore, in a case of doubt, the validity of a marriage must be upheld until the contrary is proven.
Can. 1095 The following are incapable of contracting marriage:1/ those who lack the sufficient use of reason;
2/ those who suffer from a grave defect of discretion of judgment concerning the essential matrimonial rights and duties mutually to be handed over and accepted;
3/ those who are not able to assume the essential obligations of marriage for causes of a psychic nature.
Can. 1107 Even if a marriage was entered into invalidly by reason of an impediment or a defect of form, the consent given is presumed to persist until its revocation is established.