I have got to hand it to you: That is the most detailed and well-worded post about 'somebody being bored' I have read in my entire life (and I am "ancient"). In fact I kind of feel like a voyeur for learning so much about you all at once.
I, on the other hand, am way too busy for my own good, but have a pre-written suggestion I'd like to share with you.
If you are interested, search for "I am bored." here:
Yatsufusa's Frequently Given Replies
https://yatsufusa.newgrounds.com/news/post/1487260
AlfaFranek
Think about it, going outside, even for an hour, is an instant gratification. Sunlight gives some vitamin D, cold and/or wind sobers mind, constant walking makes better blood circulation.
I know that's not what you meant by instant gratification, but those are still reasons to go outside.
I'm a sad fuck too, altough maybe to not same degree, I overthink, I dont do much, I'm lazy and I'm bad socially. Just like you. But all of that bothers me, so even tho its not pleasant, I try to be better. I try to walk outside, I try to not watch random shit on internet, I try to draw, I try to be better socially. It's all awkard, out of my comfort zone, but I feel just a bit better and its worth to not be a sad fuck.