Telling a friend you're not OK
Most of us were never shown how to do this. We know how to help a friend move a sofa. Nobody taught us how to say "I'm not doing well". So here's the procedure.
Pick the person
Not the ideal listener. The available one. Someone who has been decent to you and doesn't gossip. An old friend you haven't called in a year is fine. People value being contacted more than the sender expects. Evidence: decent
One person is enough. This is not an announcement.
Pick the setting
Side by side beats face to face: a walk, a drive, a job that needs two people. There's less staring and something to do with your hands. Evidence: worth trying
A message is a fine way to start. It lets him answer when he's ready.
The first sentence
This is the hard part, so borrow one:
Got ten minutes this week? Something's been weighing on me and I'd rather say it to you than keep chewing on it.
I'm not great lately. Nothing dramatic. I could use a beer and an ear.
Can I tell you something, and you just listen? I don't need it fixed.
You don't need the whole story ready. One true sentence is enough: "Work is grinding me down." "Things at home are bad." "I'm not sleeping." The rest follows, or it doesn't, and either is fine.
Say what you need
Most friends panic because they think they have to solve it. Take that job off him at the start:
I don't need advice. I need to say it out loud to someone.
Or, if you do want his view:
Tell me straight what you'd do.
If it goes badly
He might joke, change the subject, or tell you it's not that bad. That's usually discomfort, not rejection. He wasn't shown how to do this either.
Try once more, plainly: "I'm serious. It's been rough." If he still can't, he's not your person for this. Pick another. One bad reaction is information about him, not about you.
Afterwards
You'll probably feel exposed the next day. That passes. Putting a thing into words makes it weigh less. Evidence: decent
Send a short message: "Thanks for the other night." It closes the loop, and it makes the next time easier for both of you.
If what you're carrying is heavier than a friend can hold, a doctor is the next step, not a failure of the first one.