How difficult would it be for me to get a divorce if I’ve been married for less than a month?

A short term marriage is easier to end as it would be a matter of returning each of you to the position you were in prior to the marriage. Property and debt would have to be separated and resolved.

Not difficult.. you go through a typical divorce matter.. divide up the marriage assets (what happens to the wedding gifts) and in as little as 60 days you can be divorced.

In Michigan, a divorce without children will take three months.

Since Michigan is a "no fault" divorce state all you would need to state in the complaint that you file or have filed by your attorney is "there has been a breakdown in the marital relationship to the extent that the objects of matrimony have been destroyed and there remains no likelihood that the marriage can be preserved". I assume that there are no children and you are not pregnant at the present time. If that is the case you would be eligible to have a Judgment of Divorce granted after the passage of 60 days after your husband was served with the divorce complaint unless he files an answer stating his position or counterclaim which would need to be resolved by the Judge before a Judgment could be granted.

Since Michigan is a no fault divorce state, you file at any time for divorce.

You could have grounds for an annulment. Either way there is nothing precluding you from filing.

Should be reasonably uncomplicated.