does your employer participate in an EAP or any mental health support programs?
If so, going through that program or your HR department is probably a better way to proceed. Talking to your direct boss may impact your relationship, perception or otherwise lead to negative consequences. Many corporate employers in the US provide employees with access to mental health benefits and programs that include substance treatment in a confidential way that help communicate the need and work with the employee - without the specifics of what is going on being revealed to superiors or co-workers.
You may be entitled to take short-term disability for treatment and return to your position or a position of equal pay and responsibility without consequence.
If I were you I would contact your EAP or reach out to your HR department to inquire about the availability of confidential mental health services to support "a personal issue in my life right now".