Try to relax and sleep more during the week. You’re most likely exhausted by the weekend and your mind and body are trying to catch up from the lack of rest. So switch off from work, relax your mind and body, entertain yourself, play, and sleep more.
Free time is a great time to exercise, read, be with nature, be with family, be with friends. All of those things will refresh your spirit and/or body.
It may take several weeks after giving up going out on weeknights, avoiding video games, avoiding drinking, eating “right”, going to the gym, and getting to bed on time before you feel peppy enough to enjoy your weekends.
But unless you’re ill (which is worth considering if it persists), you should soon be able to enjoy and energetic self on the weekends.