At the gym today, not because I'm motivated or enthusiastic, just doing my best to show up. I'm having a tough time for a few different reasons. Today I showed up because it was the best I can do today. Hopefully the good days will get mire frequent soon.
Showing up is still an accomplishment. I know there are some days that all I can do is read a book walking on the treadmill or exercise bike. But at least by going I keep the habit and it makes it easier to maintain the momentum to go in the future.
One thing that helps me is to try and make a connection with some of the other regulars at the gym. Kinda turn into a 'Cheers' moment. You know when Norm walks into the bar and everybody shouts out his name? I know you're in England but I'm guessing that show made it over there.
It is tough going to the gym when things difficult and the mind is tired. Well done for even showing up! Take pride in that.
Try to do something that's fun and easier so your brain gets the reward of accomplishment. That, done over time, will convince your mind to associate the gym with good feelings of achievement, which will make it easier when things are tough.