Maybe you can simply accept it. You get less energy because the sun isn't there as much to give it to you. You're the only one who feels this way, there are others like you, and I think it's normal too. I think you should accept that you're this way and not try to energise yourself too much if it doesn't happen naturally. Or, another drastic step, you could move to different parts of the globe during winter? But that doesn't sound entirely healthy either to completely skip seasons.