Jo G and S H have the right idea.
I looked at your profile to see how old you are. No info at all. I was trying to find something to go on.
Back when I was dating, this would have been very confusing. Now it would be very confusing, if I was dating. I only asked my friends or potential friends out on dates. The reason for the date was to get to know them better to see if they would be suitable partners/spouses.
You told him you don't think he is worth knowing better. If you do the bar thing, you will be telling him you do think he is worth knowing better. If you are trying to apologize, you did that. Leave him alone. Don't make him feel he needs to persue you further. Forget the thank you note. Forget the gift card. Forget the Sorry note. Let things alone.
If you met me at my favorite bar and bought me a drink, I'd think you were interested. Leave the poor guy alone. Men look at things differently than women. Leave him alone unless you are trying to establish a dating relationship. But you said you aren't interested. Leave him alone.
(Sorry to be so repetitive. I've had a broken arm, impacted wisdom teeth, broken ankle, broken knee cap and been hit in the face with a high fly ball requiring stitches. None of those was as painful as the times I had a broken heart.)
Good luck to you and yours.