This is no reason to abandon your attempts at applying. Many people have mental health treatment and even hospitalizations that complete the process just fine.
The key is to be open and honest about it, and to make sure you read every single question carefully so as to not omit any information.
The information rocket listed pertains to the older version of the SF-86. That version of the form is not used nearly as much as the newer version. The newer version does not have the line that excludes treatment due to grief.
You’ll mark that yes, you’ve been hospitalized. And include all the details required.
Also make sure to carefully read the other questions in that section. Especially the question about being diagnosed with any of the listed diagnoses. I see people mess that up constantly. They think that because they listed the hospitalization, they’re finished.
It sounds like yours is a pretty straight forward situation, but just be sure to double check. You’ll be able to mark that it was a voluntary admission and provide all the details of the treatment. And you’ll go through it with your investigator during the interview.
Definitely not SOL.