I got in great shape with bad workouts
Friends have asked me how I got into great shape and have stayed that way for years. I like to tell them two words: "bad workouts."
There's a big myth amongst people who promote fitness stuff online and those who don't go to the gym regularly that going to the gym is this Big Thing. You have to rev yourself up, pack and prep everything, lay out your precise plan, and only then can you go and make progress towards your fitness goal.
After years of working out, I can assure you that's just not true. What moves things forward is going in and doing the workouts. Regardless of your emotional state, or how much you want to (or don't want to) do it, get in there and work out.
Even the workout itself can be lackluster. Just can't bring yourself to do that third set? It's fine. Skip it. Feels like you should have a few more reps, but you're exhausted from a long week? Okay, rack it. The volume will still accumulate. You're still making progress.
I know this works because it's what worked for me. I'd estimate more than half my workouts were "bad workouts" in this sense. I never stopped going to the gym though. I didn't talk myself into believing that my bad workouts were worthless.
I kept going through multiple job changes, getting married, becoming a dad, and traveling for work. As a result, I look better than most people my age and I feel great physically.
Don't quit. Keep doing the bad workouts.