How do you get motivation to stick around?

You know how when you're like chillen browsing the internet at like 3am in the morning and all of a sudden you feel like doing something super productive? How do you get that motivation to stay? I mean like I really want to do the stuff that I think about when I'm up in the middle of the night but I guess I just don't because it's kind of stupid to go jogging at 3am, or like I know I'm gonna be really lazy to put away all my paint if I feel like painting something, OR when I finally get the feeling of doing a blog post and I sit down and do it all, I don't want to finish it because I'm lazy. How am I supposed to continue what I do if I'm so lazy!?

So whats been happening lately is that I've been indulging hardcore in really bad food. Usually I can eat it and just be whatever about it yet lately I've been feeling so guilty... like hide in my cave/never go out to see the world/backing out of plans with people/never see the light of day guilty. Plus I can't seem to get ahold of that 3am motivation during the day when it matters. For example, I'd much rather be sitting on my bed eating soft and chewy chocolate chip cookies typing this crap instead of out getting exercise and being healthier. I have so many excuses, but I'm too lazy to discipline myself.

I can reason with myself by saying things like: I have to work tomorrow, I already went to costco today so that's enough for the day, blah blah... just stuff that at the moment sounds right, if only to give me some type of relief of guilt or something like that. I don't know haha, but seriously, I have so much planned but I have so much trouble finishing what I start.

I think maybe my problem can be resolved with making lists. I like to complete stuff off of lists. But I lose lists constantly.
Maybe I'll just be lazy forever.
Probably.